Aryl pyridazinone derivatives and their use as H3 receptor ligands

ABSTRACT

The present invention is directed to novel pyridazinone derivatives that mediate enzymatic activity. In particular, the compounds and/or their pharmaceutically acceptable salts may be effective in the treatment of diseases or disease states related to the activity of the histamine H 3  receptor, including, for example, neurodegenerative disorders, sleep/wake disorders, attention deficit hyperactivity disorder and cognition/cognitive disorders.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuing application of U.S. application Ser.No. 11/881,001 filed Jul. 25, 2007, which claims the benefit of U.S.Provisional Application Ser. No. 60/833,164 filed Jul. 25, 2006, thedisclosure of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention is related to pyridazinone derivatives, their useas H₃ inhibitors, processes for their preparation, and pharmaceuticalcompositions thereof.

BACKGROUND OF THE INVENTION

Histamine is a well established modulator of neuronal activity. At leastfour subtypes of histamine receptors have been reported in theliterature—H₁, H₂, H₃, H₄. The histamine H₃ receptors play a key role inneurotransmission in the central nervous system. The H₃ receptor wasdiscovered in 1983 originally on histamine-containing neurons where itwas shown to function presynaptically, regulating the release andsynthesis of the biogenic amine histamine (Arrang et al, 1983) now awell established neurotransmitter. H₃ receptors are predominatelyexpressed in the brain, localizing to the cerebral cortex, amygdala,hippocampus, striatum, thalamus and hypothalamus. H₃ receptors are alsolocalized presynaptically on histaminergic nerve terminals and act asinhibitory autoreceptors (Alguacil and Perez-Garcia, 2003; Passani etal, 2004; Leurs at al, 2005; Celanire et al, 2005; Witkin and Nelson,2004). When these receptors are activated by histamine, histaminerelease is inhibited. H₃ receptors can also be found in the periphery(skin, lung, cardiovascular system, intestine, GI tract, etc). H₃receptors are also involved in presynaptic regulation of the release ofacetylcholine, dopamine, GABA, glutamate and serotonin (seeRepka-Ramirez, 2003; Chazot and Hann, 2001; Leurs et al, 1998). The H₃receptor demonstrates a high degree of constitutive or spontaneousactivity (e.g., receptor is active in the absence of agoniststimulation) in vitro and in vivo, thus, ligands to the receptor candisplay, agonist, neutral antagonist or inverse agonist effects.

The location and function of histaminergic neurons in the CNS suggeststhat compounds interacting with the H₃ receptor may have utility in anumber of therapeutic applications including narcolepsy or sleep/wakedisorders, feeding behavior, eating disorders, obesity, cognition,arousal, memory, mood disorders, mood attention alteration, attentiondeficit hyperactivity disorder (ADHD), Alzheimer's disease/dementia,schizophrenia, pain, stress, migraine, motion sickness, depression,psychiatric disorders and epilepsy (Leers et al, 2005; Witkin andNelson, 2004, Hancock and Fox 2004; Esbenshade et al. 2006). An H₃antagonist/inverse agonist could be important for gastrointestinaldisorders, respiratory disorders such as asthma, inflammation, andmyocardial infarction.

Ohtake et al. (US 2006/0178375 A1) disclosed compounds that reportedlyexhibit histamine receptor H₃ antagonist or inverse agonist activity andmay be useful for the treatment or prevention of obesity, diabetes,hormonal secretion abnormality, or sleep disorders.

Celanire et al. (WO 2006/103057 A1 and WO 2006/103045) have disclosedcompounds comprising an oxazoline or thiazoline moiety, processes forpreparing them, their pharmaceutical compositions and their uses as H₃ligands.

Bertrand et al. (WO 2006/117609 A2) disclosed novel histamine H₃receptor ligands, processes for their preparation, and their therapeuticapplications.

Schwartz et al. (WO 2006/103546 A2) disclosed certain methods oftreatment for Parkinson's disease, obstructive sleep apnea, narcolepsy,dementia with Lewy bodies, and/or vascular dementia using non-imidazolealkylamine derivatives that are antagonists of the H₃ receptors ofhistamine.

Apodaca et al. (EP 1 311 482 B1) disclosed certain non-imidazolearyloxypiperidines as H₃ receptor ligands, their synthesis, and theiruse for the treatment of disorders and conditions mediated by thehistamine receptor.

Xu et al. disclosed certain 6-substitutedphenyl-4,5-dihydro-3(2H)-pyridazinones, their synthesis, and rabbitplatelet aggregation inhibitory activity induced by ADP in vitro.

Thus, there is a need for novel classes of compounds that possess thebeneficial properties. It has been discovered that currently disclosedclass of compounds, referred to herein as substituted pyridazinonederivatives, are useful as agents for treating or preventing variousdiseases or disorders disclosed herein.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed, in part, to novelpyridazinone compounds which may be useful as H₃ inhibitors, and thusmay be useful, inter alia, in methods for treating diseases, disorders,and/or conditions that may be mediated or modulated by inhibition of H₃,or otherwise associated with the H₃ receptor system, including, forexample, narcolepsy or sleep/wake disorders, feeding behavior, eatingdisorders, obesity, cognition, arousal, memory, mood disorders, moodattention alteration, attention deficit hyperactivity disorder (ADHD),Alzheimer's disease/dementia, schizophrenia, pain, stress, migraine,motion sickness, depression, psychiatric disorders, epilepsy,gastrointestinal disorders, respiratory disorders (such as asthma),inflammation, and myocardial infarction. In preferred form, the novelcompounds of the invention have the following formula I*:

or a stereoisomeric form, mixture of stereoisomeric forms, or apharmaceutically acceptable salt forms thereof, wherein:

-   X and X^(a) are each independently CH or N;-   Y is S(O)_(q), O, or NR¹⁵;-   R¹ is NR¹⁰R¹¹ or a 4- to 9-membered heterocycloalkyl ring containing    1 or 2 nitrogen atoms and optionally substituted with 1 to 3 R²⁰    groups;-   R² is

wherein:

-   -   when X and X^(a) are both CH, then R² is meta or para to the        Y—(CHR⁴)_(m)—R¹ group; and    -   when either X or X^(a) are N, then R² is para to the        Y—(CHR⁴)_(m)—R¹ group;

-   each R³ is:    -   independently H, F, Cl, Br, I, OR²¹, NR²³R²⁴, NO₂, CN, CF₃,        C₁-C₆alkyl, C(═O)R²¹, CO₂R²¹, or C(═O)NR²³R²⁴; or    -   when R³ is ortho to R², and R² is (i), (ii), (iv), (vi), or        (ix), then R³ and R¹⁴ taken together may form —(CH₂)_(s)—,        —CH₂Z—, —ZCH₂—, —ZCH₂CH₂— or CH₂CH₂Z—; wherein Z is O, S(O)_(y),        or NR²⁷; or    -   when R³ is ortho to R², and R² is (iv), (v), or (viii), then R³        and R¹³ taken together may form —(CH₂)_(s)—, —CH₂Z—, —ZCH₂—,        —ZCH₂CH₂— or CH₂CH₂Z—; or    -   when R³ is ortho to R², and R² is (viii), then R³ and R^(13b)        taken together may form —(CH₂)_(s)—, —CH₂Z—, —ZCH₂—, —ZCH₂CH₂—        or CH₂CH₂Z—; or    -   when R³ is ortho to X^(a) and R² is ortho to R³ and meta to        X^(a), then R² and R³ taken together may form:

-   each R⁴ is independently H, C₁-C₆alkyl, or OR²¹, wherein the alkyl    group is optionally substituted with 1 to 3 R²⁰ groups;-   R¹⁰ and R¹¹ are each independently H, C₁-C₆alkyl, or    C₃-C₆cycloalkyl, wherein the alkyl or cycloalkyl group is optionally    substituted with 1 to 3 R²⁰ groups;-   R¹² is H, C₁-C₆alkyl, cycloalkyl, aryl, arylalkyl, heteroaryl,    heterocycloalkyl, C(═O)R²⁷, or CO₂R²⁷, wherein the alkyl,    cycloalkyl, aryl, arylalkyl, heteroaryl, or heterocycloalkyl group    is optionally substituted with 1 to 3 R²⁰ groups;-   R¹³ and R¹⁴ are each independently H, C₁-C₆alkyl, aryl, arylalkyl    C₁-C₆alkoxyl, S(═O)_(y)—C₁-C₆alkyl, cycloalkyl, heterocycloalkyl, or    heteroaryl;-   R^(13a), R^(13b), R^(13c), and R^(14a) are each independently H,    C₁-C₆alkyl; or R¹³ and R¹⁴, taken together with the carbon atoms    through which they are connected form a fused phenyl, thienyl,    pyrrolyl, oxazolyl, pyridinyl, or C₃-C₆cycloalkyl ring; or R^(13b)    and R¹⁴, or R¹³ and ^(14a), or R^(13b) and ^(14a), or R^(13c) and    R^(14a), taken together with the carbon atoms through which they are    connected form a fused C₃-C₆cycloalkyl ring; or R¹³ and R^(13a), or    R¹⁴ and R^(14a), taken together with the carbon atom to which they    are attached form a C₃-C₈cycloalkyl ring; provided that no more than    one pair of R¹³ and R¹⁴, R^(13b) and R¹⁴, R¹³ and R^(14a), R^(13b)    and R^(14a), R^(13c) and R^(14a), R¹³ and R^(13a), and R¹⁴ and    R^(14a) are taken together with the carbon atoms through which they    are connected or to which they are attached to form a ring; and    wherein the fused phenyl, thienyl, pyrrolyl, oxazolyl, pyridinyl, or    cycloalkyl ring is optionally substituted with 1 to 3 R²⁰ groups;-   R¹⁵ is H, C₁-C₆ alkyl, C(═O)R²⁵, CO₂R²⁵;-   R²⁰ at each occurrence is independently, H, F, Cl, Br, I, OR²¹,    OR²², NR²³R²⁴, NHOH, NO₂, CN, CF₃, C₁-C₆ alkyl optionally    substituted with OR²⁶, C₂-C₆ alkenyl, C₂-C₆ alkynyl,    C₃-C₇cycloalkylC₀-C₄alkyl, 3- to 7-membered    heterocycloalkylC₀-C₄alkyl, phenyl, 5- or 6-membered    heteroarylC₀-C₄alkyl, arylalkyl, (═O), C(═O)R²¹, CO₂R²¹, OC(═O)R²¹,    C(═O)NR²³R²⁴, NR²⁷C(═O)R²¹, NR²⁷C(═O)OR²¹, OC(═O)NR²³R²⁴,    NR²⁷C(═S)R²¹, or S(O)_(q)R²¹;-   each R²¹ is independently H, C₁-C₆alkyl, aryl, or arylalkyl;-   each R²² is independently the residue of an amino acid after the    hydroxyl group of the carboxyl group is removed;-   each R²³ and R²⁴ is independently selected from H, C₁-C₆alkyl, and    aryl, or R²³ and R²⁴, together with the nitrogen atom to which they    are attached, form a 3 to 7 membered heterocyclic ring optionally    substituted with ═O;-   R²⁵ is C₁-C₆alkyl, aryl, or alkylaryl;-   R²⁶ is H, C₁-C₆alkyl, aryl, or alkylaryl;-   R²⁷ is H or C₁-C₆alkyl;-   m is 1, 2, 3, 4, or 5 when R¹ is attached via a nitrogen atom, and m    is 0, 1, 2, 3, 4, or 5 when R¹ is attached via a carbon atom;-   n is 1, 2, or 3;-   q is 0, 1, or 2;-   s is 1, 2, or 3; and-   y is 0, 1, or 2.

In another aspect, the present invention is directed to pharmaceuticalcompositions which comprise a pharmaceutically acceptable carrier and acompound of the present invention, preferably in a therapeuticallyeffective amount.

In other aspects, the present invention is directed to methods fortreating a disorder selected from the group consisting of narcolepsy orsleep/wake disorders, feeding behavior, eating disorders, obesity,cognition, arousal, memory, mood disorders, mood attention alteration,attention deficit hyperactivity disorder (ADHD), Alzheimer'sdisease/dementia, schizophrenia, pain, stress, migraine, motionsickness, depression, psychiatric disorders, epilepsy, gastrointestinaldisorders, respiratory disorders, inflammation, and myocardialinfarction in a patient in need thereof comprising administering to thepatient a therapeutically effective amount of a compound of the presentinvention.

These and other aspects of the invention will become more apparent fromthe following detailed description.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The invention is generally directed to pyridazinone derivatives,processes for their preparation, and pharmaceuticals compositions theirand methods of their pharmaceutical use.

As employed above and throughout the disclosure, the following terms,unless otherwise indicated, shall be understood to have the followingmeanings.

As used herein, the term “about” refers to a range of values from ±10%of a specified value. For example, the phrase “about 50” includes ±10%of 50, or from 45 to 55. The phrase “from about 10 to 100” includes ±10%of 10 and ±10% of 100, or from 9 to 110.

As used herein, a range of values in the form “x-y” or “x to y”, or “xthrough y”, include integers x, y, and the integers therebetween. Forexample, the phrases “1-6”, or “1 to 6” or “1 through 6” are intended toinclude the integers 1, 2, 3, 4, 5, and 6. Preferred embodiments includeeach individual integer in the range, as well as any subcombination ofintegers. For example, preferred integers for “1-6” can include 1, 2, 3,4, 5, 6, 1 to 2, 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, 2 to 5, 2 to 6,etc.

As used herein “stable compound” or “stable structure” refers to acompound that is sufficiently robust to survive isolation to a usefuldegree of purity from a reaction mixture, and preferably capable offormulation into an efficacious therapeutic agent. The present inventionis directed only to stable compounds.

As used herein, “substituted” refers to any one or more hydrogen atomson the indicated atom is replaced with a selected group referred toherein as a “substituent”, provided that the substituted atom's valencyis not exceeded, and that the substitution results in a stable compound.A substituted group has 1 to 5, preferably 1 to 3, and more preferably 1independently selected substituents. Preferred substituents include, butare not limited to F, Cl, Br, I, OH, OR, NH₂, NHR, NR₂, NHOH, NO₂, CN,CF₃, CF₂CF₃, C₁-C₆ alkyl, C₂-C₆ alkenyl, C₂-C₆ alkynyl, C₁-C₆ alkoxy,C₃-C₇ cycloalkyl, heterocyclyl, C₆-C₁₀ aryl, heteroaryl, arylalkyl, ═O,C(═O)R, COOH, CO₂R, O—C(═O)R, C(═O)NRR′, NRC(═O)R′, NRCO₂R′, OC(═O)NRR′,—NRC(═O)NRR′, —NRC(═S)NRR′, and —SO₂NRR′, wherein R and R′ are eachindependently hydrogen, C₁-C₆ alkyl, or C₆-C₁₀ aryl.

As used herein, the term “alkyl” refers to a straight-chain, or branchedalkyl group having 1 to 8 carbon atoms, preferably from 1 to 6, with 1to 3 more preferred. Exemplary alkyl groups include methyl, ethyl,propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl,isoamyl, neopentyl, 1-ethylpropyl, 3-methylpentyl, 2,2-dimethylbutyl,2,3-dimethylbutyl, hexyl, octyl, etc. The alkyl moiety ofalkyl-containing groups, such as alkoxy, alkoxycarbonyl, andalkylaminocarbonyl groups, has the same meaning as alkyl defined above.Lower alkyl groups, which are preferred, are alkyl groups as definedabove which contain 1 to 4 carbons. A designation such as “C₁-C₄ alkyl”refers to an alkyl radical containing from 1 to 4 carbon atoms. Alkylgroups may be optionally substituted.

As used herein, the term “alkenyl” refers to a straight chain, orbranched hydrocarbon chains of 2 to 8 carbon atoms having at least onecarbon-carbon double bond. A designation “C₂-C₈ alkenyl” refers to analkenyl radical containing from 2 to 8 carbon atoms. Examples of alkenylgroups include ethenyl, propenyl, isopropenyl, 2,4-pentadienyl, etc.Alkenyl groups may be optionally substituted.

As used herein, the term “alkynyl” refers to a straight chain, orbranched hydrocarbon chains of 2 to 8 carbon atoms having at least onecarbon-carbon triple bond. A designation “C₂-C₈ alkynyl” refers to analkynyl radical containing from 2 to 8 carbon atoms. Examples includeethynyl, propynyl, isopropynyl, 3,5-hexadiynyl, etc. Alkynyl groups maybe optionally substituted.

As used herein, the term “cycloalkyl” refers to a saturated or partiallysaturated mono- or bicyclic alkyl ring system containing 3 to 10 carbonatoms. Certain embodiments contain 3 to 6 carbon atoms, preferably 3 or4 carbon atoms, and other embodiments contain 5 or 6 carbon atoms. Adesignation such as “C₅-C₇ cycloalkyl” refers to a cycloalkyl radicalcontaining from 5 to 7 ring carbon atoms. Examples of cycloalkyl groupsinclude such groups as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl,cycloheptyl, cyclooctyl, pinenyl, pinanyl, and adamantanyl. Cycloalkylgroups may be optionally substituted.

As used herein, the term “aryl” refers to a substituted orunsubstituted, mono- or bicyclic hydrocarbon aromatic ring system having6 to 12 ring carbon atoms. Examples include phenyl and naphthyl.Preferred aryl groups include unsubstituted or substituted phenyl andnaphthyl groups. Included within the definition of “aryl” are fused ringsystems, including, for example, ring systems in which an aromatic ringis fused to a cycloalkyl ring. Examples of such fused ring systemsinclude, for example, indane, indene, and tetrahydronaphthalene. Arylgroups may be optionally substituted.

As used herein, the terms “heterocycle”, “heterocyclic” or“heterocyclyl” refer to a substituted or unsubstituted carbocyclic groupin which one or more ring carbon atoms are replaced by at least onehetero atom such as —O—, —N—, or —S—. Certain embodiments include 4 to 9membered rings preferably 3 to 7 membered rings, and other embodimentsinclude 5 or 6 membered rings. The nitrogen and sulfur heteroatoms maybe optionally oxidized, and the nitrogen may be optionally substitutedin non-aromatic rings. Heterocycles are intended to include heteroaryland heterocycloalkyl groups. Heterocyclic groups may be optionallysubstituted.

As used herein, the term “heteroaryl” refers to an aromatic groupcontaining 5 to 10 ring carbon atoms in which one or more ring carbonatoms are replaced by at least one hetero atom such as —O—, —N—, or —S—.Certain embodiments include 5 or 6 membered rings. Examples ofheteroaryl groups include pyrrolyl, furanyl, thienyl, pyrazolyl,imidazolyl, thiazolyl, isothiazolyl, isoxazolyl, oxazolyl, oxathiolyl,oxadiazolyl, triazolyl, oxatriazolyl, furazanyl, tetrazolyl, pyridyl,pyrazinyl, pyrimidinyl, pyridazinyl, triazinyl, picolinyl, indolyl,isoindolyl, indazolyl, benzofuranyl, isobenzofuranyl, purinyl,quinazolinyl, quinolyl, isoquinolyl, benzoimidazolyl, benzothiazolyl,benzothiophenyl, thianaphthenyl, benzoxazolyl, benzisoxazolyl,cinnolinyl, phthalazinyl, naphthyridinyl, and quinoxalinyl. Includedwithin the definition of “heteroaryl” are fused ring systems, including,for example, ring systems in which an aromatic ring is fused to aheterocycloalkyl ring. Examples of such fused ring systems include, forexample, phthalamide, phthalic anhydride, indoline, isoindoline,tetrahydroisoquinoline, chroman, isochroman, chromene, and isochromene.Heteroaryl groups may be optionally substituted. In certain preferredembodiments, heteroaryl is pyridinyl, more preferably pyridine-2-yl, orthienyl

As used herein, the term “heterocycloalkyl” refers to a cycloalkyl groupin which one or more ring carbon atoms are replaced by at least onehetero atom such as —O—, —N—, or —S—. Certain embodiments include 4 to 9membered rings, preferably 3 to 7, more preferably 3 to 6 memberedrings, and other embodiments include 5 or 6 membered rings. Examples ofheterocycloalkyl groups include pyrrolidinyl, pyrrolinyl,imidazolidinyl, imidazolinyl, pirazolidinyl, pirazolinyl, pyrazalinyl,piperidinyl, piperazinyl, hexahydropyrimidinyl, morpholinyl,thiomorpholinyl, tetrahydrofuranyl, dithiolyl, oxathiolyl, dioxazolyl,oxathiazolyl, pyranyl, oxazinyl, oxathiazinyl, and oxadiazinyl,preferably pyrrolidinyl, morpholinyl, piperidinyl, orazapanyl, morepreferably pyrrolidinyl or piperidinyl. Heterocycloalkyl groups may beoptionally substituted.

As used herein, the term “arylalkyl” refers to an alkyl group that issubstituted with an aryl group. Examples of arylalkyl groups include,but are not limited to, benzyl, bromobenzyl, phenethyl, benzhydryl,diphenylmethyl, triphenylmethyl, diphenylethyl, naphthylmethyl, etc.preferably benzyl. Arylalkyl groups may be optionally substituted.

As used herein, the term “amino acid” refers to a group containing bothan amino group and a carboxyl group. Embodiments of amino acids includeα-amino, β-amino, γ-amino acids. The α-amino acids have a generalformula HOOC—CH(side chain)-NH₂. The amino acids can be in their D, L orracemic configurations. Amino acids include naturally-occurring andnon-naturally occurring moieties. The naturally-occurring amino acidsinclude the standard 20 α-amino acids found in proteins, such asglycine, serine, tyrosine, proline, histidine, glutamine, etc.Naturally-occurring amino acids can also include non-α-amino acids (suchas β-alanine, γ-aminobutyric acid, homocysteine, etc.), rare amino acids(such as 4-hydroxyproline, 5-hydroxylysine, 3-methylhistidine, etc.) andnon-protein amino acids (such as citrulline, ornithine, canavanine,etc.). Non-naturally occurring amino acids are well-known in the art,and include analogs of natural amino acids. See Lehninger, A. L.Biochemistry, 2^(nd) ed.; Worth Publishers: New York, 1975; 71-77, thedisclosure of which is incorporated herein by reference. Non-naturallyoccurring amino acids also include α-amino acids wherein the side chainsare replaced with synthetic derivatives. In certain embodiments,substituent groups for the compounds of the present invention includethe residue of an amino acid after removal of the hydroxyl moiety of thecarboxyl group thereof; i.e., groups of formula —C(═O)CH(sidechain)-NH₂. Representative side chains of naturally occurring andnon-naturally occurring α-amino acids include are shown below in TableA.

TABLE A H CH₃— HO—CH₂— C₆H₅—CH₂— HO—C₆H₄—CH₂—

HS—CH₂— HO₂C—CH(NH₂)—CH₂—S—S—CH₂— CH₃—CH₂— CH₃—S—CH₂—CH₂—CH₃—CH₂—S—CH₂—CH₂— HO—CH₂—CH₂— C₅H₉— C₆H₁₁— C₆H₁₁—CH₂— CH₃—CH(OH)—HO₂C—CH₂—NHC(═O)—CH₂— HO₂C—CH₂— HO₂C—CH₂—CH₂— NH₂C(═O)—CH₂—NH₂C(═O)—CH₂—CH₂— (CH₃)₂—CH— (CH₃)₂—CH—CH₂— CH₃—CH₂—CH₂—H₂N—CH₂—CH₂—CH₂— H₂N—C(═NH)—NH—CH₂—CH₂—CH₂— H₂N—C(═O)—NH—CH₂—CH₂—CH₂—CH₃—CH₂—CH(CH₃)— CH₃—CH₂—CH₂—CH₂— H₂N—CH₂—CH₂—CH₂—CH₂—

As used herein, the term “subject” or “patient” refers to a warm bloodedanimal such as a mammal, preferably a human, or a human child, which isafflicted with, or has the potential to be afflicted with one or morediseases and conditions described herein.

As used herein, a “therapeutically effective amount” refers to an amountof a compound of the present invention effective to prevent or treat thesymptoms of particular disorder. Such disorders include, but are notlimited to, those pathological and neurological disorders associatedwith the aberrant activity of the receptors described herein, whereinthe treatment or prevention comprises inhibiting, inducing, or enhancingthe activity thereof by contacting the receptor with a compound of thepresent invention.

As used herein, the term “pharmaceutically acceptable” refers to thosecompounds, materials, compositions, and/or dosage forms which are,within the scope of sound medical judgment, suitable for contact withthe tissues of human beings and animals without excessive toxicity,irritation, allergic response, or other problem complicationscommensurate with a reasonable benefit/risk ratio.

As used herein, the term “unit dose” refers to a single dose which iscapable of being administered to a patient, and which can be readilyhandled and packaged, remaining as a physically and chemically stableunit dose comprising either the active compound itself, or as apharmaceutically acceptable composition, as described hereinafter.

As used herein, “pharmaceutically acceptable salts” refer to derivativesof the disclosed compounds wherein the parent compound is modified bymaking acid or base salts thereof. Examples of pharmaceuticallyacceptable salts include, but are not limited to, mineral or organicacid salts of basic residues such as amines; alkali or organic salts ofacidic residues such as carboxylic acids; and the like. Thepharmaceutically acceptable salts include the conventional non-toxicsalts or the quaternary ammonium salts of the parent compound formed,for example, from non-toxic inorganic or organic acids. For example,such conventional non-toxic salts include those derived from inorganicacids such as hydrochloric, hydrobromic, sulfuric, sulfamic, phosphoric,nitric and the like; and the salts prepared from organic acids such asacetic, propionic, succinic, glycolic, stearic, lactic, malic, tartaric,citric, ascorbic, pamoic, maleic, hydroxymaleic, phenylacetic, glutamic,benzoic, salicylic, sulfanilic, 2-acetoxybenzoic, fumaric,toluenesulfonic, methanesulfonic, ethane disulfonic, oxalic, isethionic,and the like. These physiologically acceptable salts are prepared bymethods known in the art, e.g., by dissolving the free amine bases withan excess of the acid in aqueous alcohol, or neutralizing a freecarboxylic acid with an alkali metal base such as a hydroxide, or withan amine.

Compounds described herein throughout, can be used or prepared inalternate forms. For example, many amino-containing compounds can beused or prepared as an acid addition salt. Often such salts improveisolation and handling properties of the compound. For example,depending on the reagents, reaction conditions and the like, compoundsas described herein can be used or prepared, for example, as theirhydrochloride or tosylate salts. Isomorphic crystalline forms, allchiral and racemic forms, N-oxide, hydrates, solvates, and acid salthydrates, are also contemplated to be within the scope of the presentinvention.

Certain acidic or basic compounds of the present invention may exist aszwitterions. All forms of the compounds, including free acid, free baseand zwitterions, are contemplated to be within the scope of the presentinvention. It is well known in the art that compounds containing bothamino and carboxy groups often exist in equilibrium with theirzwitterionic forms. Thus, any of the compounds described hereinthroughout that contain, for example, both amino and carboxy groups,also include reference to their corresponding zwitterions.

As used herein, “prodrug” refers to compounds specifically designed tomaximize the amount of active species that reaches the desired site ofreaction, which are of themselves typically inactive or minimally activefor the activity desired, but through biotransformation are convertedinto biologically active metabolites.

Accordingly, prodrugs include, for example, compounds described hereinin which a hydroxy, amino, or carboxy group is bonded to any group that,when the prodrug is administered to a mammalian subject, cleaves to forma free hydroxyl, free amino, or carboxylic acid, respectively. Examplesinclude, but are not limited to, acetate, formate and benzoatederivatives of alcohol and amine functional groups; and alkyl,cycloalkyl, aryl, and alkylaryl esters such as methyl, ethyl, propyl,isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, cyclopropyl, phenyl,benzyl, and phenethyl esters, and the like.

Compounds described herein may contain one or more asymmetricallysubstituted carbon atoms, and may be isolated in optically active orracemic forms. Thus, all isomeric forms of a structure, including allstereogenic (such as enantiomeric, diastereomeric, and/or meso forms,whether chiral or racemic), all achiral, all geometric, and/or allconformational isomeric forms are intended, unless the specificstereochemical or other isomeric form is specifically indicated and/orachiral. It is well known in the art how to prepare and isolate suchisomeric forms of a structure including those having stereogenic centersincluding those stereogenic forms wherein the structure is present inoptically active form. For example, mixtures of stereoisomers may beseparated by standard techniques including, but not limited to,resolution of racemic forms, normal, reverse-phase, and chiralchromatography, preferential salt formation, recrystallization, and thelike, or by chiral synthesis either from chiral starting materials or bydeliberate synthesis of target chiral centers.

As used herein, the term “stereoisomers” refers to compounds that haveidentical chemical constitution, but differ as regards the arrangementof the atoms or groups in space.

The terms “treatment” and “treating” as used herein include preventative(e.g., prophylactic), curative and/or palliative treatment.

When any variable occurs more than one time in any constituent or in anyformula, its definition in each occurrence is independent of itsdefinition at every other occurrence. Combinations of substituentsand/or variables are permissible only if such combinations result instable compounds.

It is believed the chemical formulas and names used herein correctly andaccurately reflect the underlying chemical compounds. However, thenature and value of the present invention does not depend upon thetheoretical correctness of these formulae, in whole or in part. Thus itis understood that the formulas used herein, as well as the chemicalnames attributed to the correspondingly indicated compounds, are notintended to limit the invention in any way, including restricting it toany specific tautomeric form or to any specific optical or geometricisomer, except where such stereochemistry is clearly defined.

Accordingly, the present invention is directed, in part, to novelpyridazinone compounds which have the following formula I*:

or a stereoisomeric form, mixture of stereoisomeric forms, or apharmaceutically acceptable salt forms thereof, wherein:

-   X and X^(a) are each independently CH or N;-   Y is S(O)_(q), O, or NR¹⁵;-   R¹ is NR¹⁰R¹¹ or a 4- to 9-membered heterocycloalkyl ring containing    1 or 2 nitrogen atoms and optionally substituted with 1 to 3 R²⁰    groups;-   R² is

wherein:

-   -   when X and X^(a) are both CH, then R² is meta or para to the        Y—(CHR⁴)_(m)—R¹ group; and    -   when either X or X^(a) are N, then R² is para to the        Y—(CHR⁴)_(m)—R¹ group;

-   each R³ is:    -   independently H, F, Cl, Br, I, OR²¹, NR²³R²⁴, NO₂, CN, CF₃,        C₁-C₆alkyl, C(═O)R²¹, CO₂R²¹, or C(═O)NR²³R²⁴; or    -   when R³ is ortho to R², and R² is (i), (ii), (iv), (vi), or        (ix), then R³ and R¹⁴ taken together may form —(CH₂)_(s)—,        —CH₂Z—, —ZCH₂—, —ZCH₂CH₂— or CH₂CH₂Z—; wherein Z is O, S(O)_(y),        or NR²⁷; or    -   when R³ is ortho to R², and R² is (iv), (v), or (viii), then R³        and R¹³ taken together may form —(CH₂)_(s)—, —CH₂Z—, —ZCH₂—,        —ZCH₂CH₂— or CH₂CH₂Z—; or    -   when R³ is ortho to R², and R² is (viii), then R³ and R^(13b)        taken together may form —(CH₂)_(s)—, —CH₂Z—, —ZCH₂—, —ZCH₂CH₂—        or CH₂CH₂Z—; or    -   when R³ is ortho to X^(a) and R² is ortho to R³ and meta to        X^(a), then R² and R³ taken together may form:

-   each R⁴ is independently H, C₁-C₆alkyl, or OR²¹, wherein the alkyl    group is optionally substituted with 1 to 3 R²⁰ groups;-   R¹⁰ and R¹¹ are each independently H, C₁-C₆alkyl, or    C₃-C₆cycloalkyl, wherein the alkyl or cycloalkyl group is optionally    substituted with 1 to 3 R²⁰ groups;-   R¹² is H, C₁-C₆alkyl, cycloalkyl, aryl, arylalkyl, heteroaryl,    heterocycloalkyl, C(═O)R²⁷, or CO₂R²⁷, wherein the alkyl,    cycloalkyl, aryl, arylalkyl, heteroaryl, or heterocycloalkyl group    is optionally substituted with 1 to 3 R²⁰ groups;-   R¹³ and R¹⁴ are each independently H, C₁-C₆alkyl, aryl, arylalkyl    C₁-C₆alkoxyl, S(═O)_(y)—C₁-C₆alkyl, cycloalkyl, heterocycloalkyl, or    heteroaryl;-   R^(13a), R^(13b), R^(13c), and R^(14a) are each independently H,    C₁-C₆alkyl; or R¹³ and R¹⁴, taken together with the carbon atoms    through which they are connected form a fused phenyl, thienyl,    pyrrolyl, oxazolyl, pyridinyl, or C₃-C₆cycloalkyl ring; or R^(13b)    and R¹⁴, or R¹³ and ^(14a), or R^(13b) and ^(14a), or R^(13c) and    R^(14a), taken together with the carbon atoms through which they are    connected form a fused C₃-C₆cycloalkyl ring; or R¹³ and R^(13a), or    R¹⁴ and R^(14a), taken together with the carbon atom to which they    are attached form a C₃-C₈cycloalkyl ring; provided that no more than    one pair of R¹³ and R¹⁴, R^(13b) and R¹⁴, R¹³ and R^(14a), R^(13b)    and R^(14a), R^(13c) and R^(14a), R¹³ and R^(13a), and R¹⁴ and    R^(14a) are taken together with the carbon atoms through which they    are connected or to which they are attached to form a ring; and    wherein the fused phenyl, thienyl, pyrrolyl, oxazolyl, pyridinyl, or    cycloalkyl ring is optionally substituted with 1 to 3 R²⁰ groups;-   R¹⁵ is H, C₁-C₆ alkyl, C(═O)R²⁵, CO₂R²⁵;-   R²⁰ at each occurrence is independently, H, F, Cl, Br, I, OR²¹,    OR²², NR²³R²⁴, NHOH, NO₂, CN, CF₃, C₁-C₆ alkyl optionally    substituted with OR²⁶, C₂-C₆ alkenyl, C₂-C₆ alkynyl,    C₃-C₇cycloalkylC₀-C₄alkyl, 3- to 7-membered    heterocycloalkylC₀-C₄alkyl, phenyl, 5- or 6-membered    heteroarylC₀-C₄alkyl, arylalkyl, (═O), C(═O)R²¹, CO₂R²¹, OC(═O)R²¹,    C(═O)NR²³R²⁴, NR²⁷C(═O)R²¹, NR²⁷C(═O)OR²¹, OC(═O)NR²³R²⁴,    NR²⁷C(═S)R²¹, or S(O)_(q)R²¹;-   each R²¹ is independently H, C₁-C₆alkyl, aryl, or arylalkyl;-   each R²² is independently the residue of an amino acid after the    hydroxyl group of the carboxyl group is removed;-   each R²³ and R²⁴ is independently selected from H, C₁-C₆alkyl, and    aryl, or R²³ and R²⁴, together with the nitrogen atom to which they    are attached, form a 3 to 7 membered heterocyclic ring optionally    substituted with ═O;-   R²⁵ is C₁-C₆alkyl, aryl, or alkylaryl;-   R²⁶ is H, C₁-C₆alkyl, aryl, or alkylaryl;-   R²⁷ is H or C₁-C₆alkyl;-   m is 1, 2, 3, 4, or 5 when R¹ is attached via a nitrogen atom, and m    is 0, 1, 2, 3, 4, or 5 when R¹ is attached via a carbon atom;-   n is 1, 2, or 3;-   q is 0, 1, or 2;-   s is 1, 2, or 3; and

y is 0, 1, or 2.

In certain preferred embodiments, the compounds of formula I or I* areother than6-[4-(3-Diethylamino-propoxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one. Inother preferred embodiments of the compounds of formula I or I*; whenX^(a) and X are each CH, Y is O, n is 0, each R⁴ is H, m is 2, 3, or 4,R¹ is methylamino, hydroxyethylamino, pyrrolidin-1-yl, piperidin-1-yl,morpholin-4-yl, and R² is para to the Y—(CHR⁴)_(m)—R¹ group, then R² isother than 4,5-dihydro-2H-pyridazin-3-one-6-yl.

In some preferred embodiments, the present invention provides a novel offormula I:

and stereoisomeric forms, mixtures of stereoisomeric forms orpharmaceutically acceptable salt forms thereof,wherein:

-   X and X^(a) are each independently CH or N;-   Y is selected from S(O)_(q), O, and NR¹⁵;-   R¹ is NR¹⁰R¹¹ or a 4 to 9 membered heterocycloalkyl ring containing    1 or 2 nitrogen atoms and optionally substituted with 1 to 3 R²⁰    groups;-   R² is

wherein:

-   -   when X and X^(a) are both CH, then R² is meta or para to the        Y—(CHR⁴)_(m)—R¹ group; and    -   when either X or X^(a) are N, then R² is para to the        Y—(CHR⁴)_(m)—R¹ group;

-   R³ is:    -   at each occurrence is independently, H, F, Cl, Br, I, OR²¹,        NR²³R²⁴, NO₂, CN, CF₃, C₁-C₆ alkyl, C(═O)R²¹, CO₂R²¹, or        C(═O)NR²³R²⁴; or    -   when R³ is ortho to R², then R³ and R¹⁴ can combine to form        —(CH₂)_(s)—, —CH₂Z—, CH₂CH₂Z—; wherein Z is O, S(O)_(y), NR²⁷;        or    -   when R³ is ortho to X^(a) and R² is ortho to R³ and meta to        X^(a), then R² and R³ combine to form:

-   R⁴ is H, C₁-C₆ alkyl, or OR²¹, wherein the alkyl group is optionally    substituted with 1 to 3 R²⁰ groups;-   R¹⁰ and R¹¹ are each, independently H or C₁-C₆ alkyl, wherein the    alkyl group is optionally substituted with 1 to 3 R²⁰ groups;-   R¹² is H, C₁-C₆ alkyl, cycloalkyl, aryl, arylalkyl, heteroaryl,    heterocycloalkyl, C(═O)R²⁷, or CO₂R²⁷, wherein the alkyl,    cycloalkyl, aryl, arylalkyl, heteroaryl, and heterocycloalkyl groups    are optionally substituted with 1 to 3 R²⁰ groups;-   R¹³ and R¹⁴ are independently H, C₁-C₆ alkyl, aryl, or arylalkyl or    R¹³ and R¹⁴ can combine to form a fused phenyl, thienyl, pyrrolyl,    cyclopentyl or cyclohexyl ring; wherein the phenyl, thienyl,    pyrrolyl, cyclopentyl or cyclohexyl rings are optionally substituted    with 1 to 3 R²⁰ groups;-   R¹⁵ is H, C₁-C₆ alkyl, C(═O)R²⁵, CO₂R²⁵;-   R²⁰ at each occurrence is independently, H, F, Cl, Br, I, OR²¹,    OR²², NR²³R²⁴, NHOH, NO₂, CN, CF₃, C₁-C₆ alkyl optionally    substituted with OR²⁶, C₂-C₆ alkenyl, C₂-C₆ alkynyl, C₃-C₇    cycloalkyl, 3-7 membered heterocycloalkyl, phenyl, 5 or 6 membered    heteroaryl, arylalkyl, (═O), C(═O)R²¹, CO₂R²¹, OC(═O)R²¹,    C(═O)NR²³R²⁴, NR²⁷C(═O)R²¹, NR²⁷C(═O)OR²¹, OC(═O)NR²³R²⁴,    NR²⁷C(═S)R²¹, or S(O)_(q)R²¹;-   R²¹ at each occurrence is independently H, C₁-C₆ alkyl, aryl, or    arylalkyl;-   R²² at each occurrence is independently the residue of an amino acid    after the hydroxyl group of the carboxyl group is removed;-   R²³ and R²⁴ at each occurrence are each independently selected from    H, C₁-C₆ alkyl, and aryl, or R²³ and R²⁴, together with the nitrogen    atom to which they are attached, form a 3 to 7 membered heterocyclic    ring optionally substituted with ═O;-   R²⁵ is C₁-C₆ alkyl, aryl, or alkylaryl;-   R²⁶ is H, C₁-C₆ alkyl, aryl, or alkylaryl;-   R²⁷ is H or C₁-C₆ alkyl;-   m is 1, 2, 3, 4, or 5 when R¹ is attached via a nitrogen atom, and m    is 0, 1, 2, 3, 4, or 5 when R¹ is attached via a carbon atom;-   n is 0, 1, 2, or 3;-   q is 0, 1, or 2;-   s is 1, 2, or 3.

Embodiments of the present invention include those compounds of formulaI having the structure I**:

wherein:

-   Y is O;-   R¹ is NR¹⁰R¹¹ or a 5 to 6 membered heterocycloalkyl ring containing    1 or 2 nitrogen atoms and optionally substituted with 1 to 3 R²⁰    groups; or R¹ is NR¹⁰R¹¹, pyrrolidinyl or piperidyl, wherein the    pyrrolidinyl and piperidyl groups are optionally substituted with 1    to 3 R²⁰ groups; or R¹ is pyrrolidinyl or piperidyl, wherein the    pyrrolidinyl and piperidyl groups are optionally substituted with 1    to 3 R²⁰ groups;-   R⁴ is H or C₁-C₆ alkyl, wherein the alkyl group is optionally    substituted with 1 to 3 R²⁰ groups;-   R¹⁰ and R¹¹ are each, independently H or C₁-C₆ alkyl, wherein the    alkyl group is optionally substituted with 1 to 3 R²⁰ groups;-   R¹² is H, C₁-C₆ alkyl, phenyl, or benzyl, wherein the alkyl, phenyl    and benzyl groups are optionally substituted with 1 to 3 R²⁰ groups;-   R²⁰ at each occurrence is independently, H, F, Cl, Br, I, OR²¹,    OR²², NR²³R²⁴, NHOH, NO₂, CN, CF₃, C₁-C₆ alkyl optionally    substituted with OR²⁶, C₂-C₆ alkenyl, C₂-C₆ alkynyl, C₃-C₇    cycloalkyl, 3-7 membered heterocycloalkyl, phenyl, 5 or 6 membered    heteroaryl, arylalkyl, (═O), C(═O)R²¹, CO₂R²¹, OC(═O)R²¹,    C(═O)NR²³R²⁴, NR²⁷C(═O)R²¹, NR²⁷C(═O)OR²¹, OC(═O)NR²³R²⁴,    NR²⁷C(═S)R²¹, or S(O)_(q)R²¹;-   R²¹ at each occurrence is independently H, C₁-C₆ alkyl, aryl, or    arylalkyl;-   R²² at each occurrence is independently the residue of an amino acid    after the hydroxyl group of the carboxyl group is removed;-   R²³ and R²⁴ at each occurrence are each independently selected from    H, C₁-C₆ alkyl, and aryl, or R²³ and R²⁴, together with the nitrogen    atom to which they are attached, form a 3 to 7 membered heterocyclic    ring optionally substituted with ═O;-   R²⁶ is H, C₁-C₆ alkyl, aryl, or alkylaryl;-   R²⁷ is H or C₁-C₆ alkyl;-   m is 3 when R¹ is attached via a nitrogen atom, and m is 0 or 1 when    R¹ is attached via a carbon atom;-   n is 0 or 1;-   q is 0, 1, or 2.    In another embodiment, the present invention includes compounds of    formula (Ia):

wherein each variable is defined in formula I. Additional aspects of thepresent invention include compounds of formula (Ia) which incorporatethe embodiments described above for compounds of formula I, as isappropriate. For example, additional embodiments include compound offormula (Ia) with the preferred moieties of groups R¹ and R²; or R¹ andY; or R¹, R² and Y; etc.

In another embodiment, the present invention includes compounds offormula (Ib):

wherein each variable is defined in formula I. Additional aspects of thepresent invention include compounds of formula (Ib) which incorporatethe embodiments described above for compounds of formula I, as isappropriate. For example, additional embodiments include compound offormula (Ib) with the preferred moieties of groups R¹ and R²; or R¹ andY; or R¹, R² and Y; etc.

In another embodiment, the present invention includes compounds offormula (Ic):

wherein each variable is defined in formula I. Additional aspects of thepresent invention include compounds of formula (Ic) which incorporatethe embodiments described above for compounds of formula I, as isappropriate. For example, additional embodiments include compound offormula (Ic) with the preferred moieties of groups R¹ and R²; or R¹ andY; or R¹, R² and Y; etc.

In another embodiment, the present invention includes compounds offormula (Id):

wherein each variable is defined in formula I. Additional aspects of thepresent invention include compounds of formula (Id) which incorporatethe embodiments described above for compounds of formula I, as isappropriate. For example, additional embodiments include compound offormula (Id) with the preferred moieties of groups R¹; or R¹ and m; orR¹, R¹³ and R¹⁴; etc.

In another embodiment, the present invention includes compounds offormula (Ie):

wherein each variable is defined in formula I. Additional aspects of thepresent invention include compounds of formula (Ie) which incorporatethe embodiments described above for compounds of formula I, as isappropriate. For example, additional embodiments include compound offormula (Ie) with the preferred moieties of groups R¹; or R¹, R¹³ andR¹⁴; etc.

In another embodiment, the present invention includes compounds offormula (If):

wherein each variable is defined in formula I. Additional aspects of thepresent invention include compounds of formula (If) which incorporatethe embodiments described above for compounds of formula I, as isappropriate. For example, additional embodiments include compound offormula (If) with the preferred moieties of groups R¹; or R¹²; or R¹ andR¹².

In another embodiment, the present invention includes compounds offormula (Ig):

wherein each variable is defined in formula I. Additional aspects of thepresent invention include compounds of formula (Ig) which incorporatethe embodiments described above for compounds of formula I, as isappropriate. For example, additional embodiments include compound offormula (Ig) with the preferred moieties of groups R¹; or R¹²; or R¹ andR¹².

In another embodiment, the present invention includes compounds offormula (Ih):

wherein each variable is defined in formula I. Additional aspects of thepresent invention include compounds of formula (Ih) which incorporatethe embodiments described above for compounds of formula I, as isappropriate. For example, additional embodiments include compound offormula (Ih) with the preferred moieties of groups R¹; or R¹ and R¹³; orR¹, R²³ and R²⁴.

In another embodiment, the present invention includes compounds offormula (Ii):

wherein each variable is defined in formula I. Additional aspects of thepresent invention include compounds of formula (Ii) which incorporatethe embodiments described above for compounds of formula I, as isappropriate. For example, additional embodiments include compound offormula (Ii) with the preferred moieties of the R¹ and R¹² groups.

In a further embodiment of the present invention, there are includedcompounds having a structure of Formula II:

and stereoisomeric forms, mixtures of stereoisomeric forms orpharmaceutically acceptable salt forms thereof,wherein:

-   R¹ is NR¹⁰R¹¹ or a 5 to 6 membered heterocycloalkyl ring containing    1 or 2 nitrogen atoms and optionally substituted with 1 to 3 R²⁰    groups;-   R² is

-   R³ is:    -   at each occurrence is independently, H, F, Cl, Br, I, OR²¹,        NR²³R²⁴, NO₂, CN, CF₃, C₁-C₆ alkyl, C(═O)R²¹, CO₂R²¹, or        C(═O)NR²³R²⁴; or    -   when R³ is ortho to R², then R³ and R¹⁴ can combine to form        —CH₂CH₂—; or-   when R³ is ortho to X^(a) and R² is ortho to R³ and meta to X^(a),    then R² and R³ combine to form:

-   R⁴ is H or C₁-C₆ alkyl, wherein the alkyl group is optionally    substituted with 1 to 3 R²⁰ groups;-   R¹⁰ and R¹¹ are each, independently H or C₁-C₆ alkyl, wherein the    alkyl group is optionally substituted with 1 to 3 R²⁰ groups;-   R¹² is H, C₁-C₆ alkyl, phenyl, or benzyl, wherein the alkyl, phenyl    and benzyl groups are optionally substituted with 1 to 3 R²⁰ groups;-   R¹³ and R¹⁴ are independently H, C₁-C₆ alkyl, phenyl, or benzyl, or    R¹³ and R¹⁴ can combine to form a fused phenyl, thienyl, cyclopentyl    or cyclohexyl ring; wherein the phenyl, thienyl, pyrrolyl,    cyclopentyl or cyclohexyl rings are optionally substituted with 1 to    3 R²⁰ groups;-   R²⁰ at each occurrence is independently, H, F, Cl, Br, I, OR²¹,    OR²², NR²³R²⁴, NHOH, NO₂, CN, CF₃, C₁-C₆ alkyl optionally    substituted with OR²⁶, C₂-C₆ alkenyl, C₂-C₆ alkynyl, C₃-C₇    cycloalkyl, 3-7 membered heterocycloalkyl, phenyl, 5 or 6 membered    heteroaryl, arylalkyl, (═O), C(═O)R²¹, CO₂R²¹, OC(═O)R²¹,    C(═O)NR²³R²⁴, NR²⁷C(═O)R²¹, NR²⁷C(═O)OR²¹, OC(═O)NR²³R²⁴,    NR²⁷C(═S)R²¹, or S(O)_(q)R²¹;-   R²¹ at each occurrence is independently H, C₁-C₆ alkyl, aryl, or    arylalkyl;-   R²² at each occurrence is independently the residue of an amino acid    after the hydroxyl group of the carboxyl group is removed;-   R²³ and R²⁴ at each occurrence are each independently selected from    H, C₁-C₆ alkyl, and aryl, or R²³ and R²⁴, together with the nitrogen    atom to which they are attached, form a 3 to 7 membered heterocyclic    ring optionally substituted with ═O;-   R²⁶ is H, C₁-C₆ alkyl, aryl, or alkylaryl;-   R²⁷ is H or C₁-C₆ alkyl;-   m is 3 when R¹ is attached via a nitrogen atom, and m is 0 or 1 when    R¹ is attached via a carbon atom;-   n is 0 or 1;-   q is 0, 1, or 2.

As used herein, “embodiments of the present invention” is intended toinclude the full scope of compounds of any of formulas I, I*, I**,I(a-i), and II, or any combination or subcombination thereof, unlessspecifically otherwise provided.

Embodiments of the present invention include those compounds where Y isO. In other embodiments Y is S(O)_(q), or Y is NR¹⁵.

Embodiments of the present invention include those compounds where R¹ isNR¹⁰R¹¹, and those compounds where R¹⁰ and R¹¹ are each, independently Hor C₁-C₆ alkyl, preferably both are C₁-C₆ alkyl.

Embodiments of the present invention include those compounds where R¹ isa 4- to 9-membered heterocycloalkyl ring, preferably a 5- to 6-memberedheterocycloalkyl ring containing 1 or 2 nitrogen atoms, more preferably1 nitrogen atom, and optionally substituted with 1 to 3 R²⁰ groups. Incertain embodiments R¹ is an optionally substituted 5-memberedheterocycloalkyl ring containing 1 or 2 nitrogen atoms, such aspyrrolidinyl, imidazolidinyl, or pyrazolidinyl. In other embodiments, R¹is an optionally substituted 6-membered heterocycloalkyl ring containing1 or 2 nitrogen atoms, such as piperidinyl, piperazinyl, orhexahydropyrimidinyl. In certain preferred embodiments, R¹ is attachedto Y through a ring nitrogen atom. In other preferred embodiments, R¹ isattached to Y through a ring carbon atom.

In other preferred embodiments, R¹ is:

more preferably:

In certain preferred embodiments of the moiety Y—(CHR⁴)_(m)—R¹, one ormore of the carbon centers [(i.e., the subgroup “—(CHR⁴)_(m)—”), saidsubgroup which is present in the Y—(CHR⁴)_(m)—R¹ moiety “m” times] mayhave the potential to be chiral in nature. That is to say, there may be4 different groups attached to a carbon center in the subgroup. Each—(CHR⁴)— independently may be chiral and all possible stereoisomericcombinations are within the scope of the present invention. In certainmore preferable embodiments, m is 3, more preferably the moietyY—(CHR⁴)_(m)—R¹ is

Embodiments of the present invention include those compounds where R² is

In certain embodiments R² is

In other embodiments, R² is

In other embodiments, R² is

In other embodiments, R² is

In other embodiments, the R² can be a combination of R^(2A) throughR^(2E). For example, such combinations include: R^(2A), R^(2C), R^(2D),and R^(2E); R^(2A), R^(2B), R^(2D), and R^(2E); R^(2A), R^(2B), andR^(2C); R^(2A), R^(2D), and R^(2E); R^(2A), R^(2D), and R^(2E); R^(2A)and R^(2B); R^(2B) and R^(2C); R^(2D) and R^(2E); etc.

In other embodiments, R² is:

wherein:

-   -   when X and X^(a) are both CH, then R² is meta or para to the        Y—(CHR⁴)_(m)—R¹ group; and    -   when either X or X^(a) are N, then R² is para to the        Y—(CHR⁴)_(m)—R¹ group;

-   each R³ is:    -   independently H, F, Cl, Br, I, OR²¹, NR²³R²⁴, NO₂, CN, CF₃,        C₁-C₆alkyl, C(═O)R²¹, CO₂R²¹, or C(═O)NR²³R²⁴; or    -   when R³ is ortho to R², and R² is (i), (ii), (iv), (vi), or        (ix), then R³ and R¹⁴ taken together may form —(CH₂)_(s)—,        —CH₂Z—, —ZCH₂—, —ZCH₂CH₂— or CH₂CH₂Z—; wherein Z is O, S(O)_(y),        or NR²⁷; or    -   when R³ is ortho to R², and R² is (iv), (v), or (viii), then R³        and R¹³ taken together may form —(CH₂)_(s)—, —CH₂Z—, —ZCH₂—,        —ZCH₂CH₂— or CH₂CH₂Z—; or    -   when R³ is ortho to R², and R² is (viii), then R³ and R^(13b)        taken together may form —(CH₂)_(s)—, —CH₂Z—, —ZCH₂—, —ZCH₂CH₂—        or CH₂CH₂Z—; or    -   when R³ is ortho to X^(a) and R² is ortho to R³ and meta to        X^(a), then R² and R³ taken together may form:

preferably wherein R² is (i), (ii), (iv), (vi), (viii) or (ix). Incertain more preferred embodiments, R² is (iv); or it is (i); morepreferably

or it is (iii) and one of R¹³ is cyclopropyl. In other alternativelypreferred embodiments, R2 is (vi), (viii), or (ix).In some preferred embodiments, R² is:

more preferably

still more preferably

Alternatively preferred in some embodiments, R² is:

In still other embodiments, R² is:

In further embodiments of the present invention, R² is para to theY—(CHR⁴)—R¹ group. In certain embodiments when X and X^(a) are both CH,then R² is meta to the Y—(CHR⁴)—R¹ group, or R² is para to theY—(CHR⁴)—R¹ group. In other embodiments when X and X^(a) are both CH,then R² is meta or para to the Y—(CHR⁴)—R¹ group. In other embodimentsin combination with any of the three R² groups, R¹³ and R¹⁴ areindependently H, or they are each independently C₁-C₆ alkyl, or they areeach independently aryl, or they are each independently arylalkyl. Infurther embodiments of R², R¹³ and R¹⁴ can combine to form a fusedphenyl ring, or they can form a fused thienyl ring, or they can form afused pyrrolyl ring, or they can form a fused cyclopentyl ring or theycan form a fused cyclohexyl ring. An example of R¹³ and R¹⁴ combining toform a fused thienyl ring has the following structure:

Embodiments of the present invention include those compounds where n is0. Certain embodiments include those compounds where n is 1. Still otherembodiments include those compounds where n is 2.

Embodiments of the present invention include those compounds where R³ ateach occurrence is independently, H, F, Cl, Br, I, OR²¹, NR²³R²⁴, NO₂,CN, CF₃, C₁-C₆ alkyl, C(═O)R²¹, CO₂R²¹, or C(═O)NR²³R²⁴, preferably F,Cl, Br, or C₁-C₆alkyl, more preferably F. In other preferred embodimentswhen R³ is ortho to R², then R³ and R¹⁴ can combine to form —CH₂CH₂—. Incertain embodiments R³ at each occurrence is independently, H, F, Cl,Br, I, OR²¹, NR²³R²⁴, NO₂, CN, CF₃, C₁-C₆ alkyl, C(═O)R²¹, CO₂R²¹, orC(═O)NR²³R²⁴. In other embodiments, R³ is ortho to R², then R³ and R¹⁴can combine to form —(CH₂)_(s)—. An example includes a compound where sis 2, which has the following structure:

In certain embodiments of the present invention, s is 2, or s is 3. Inother embodiments, R³ and R¹⁴ can combine to form —CH₂Z— or CH₂CH₂Z—;wherein Z is O, S(O)_(y), NR²⁷. In particular, R³ and R¹⁴ can combine toform —CH₂Z— or they can combine to form CH₂CH₂Z—. In particularembodiments, Z is O and in others, Z is —S—.

In further embodiments of the present invention, R³ is ortho to X^(a)and R² is ortho to R³ and meta to X^(a), then R² and R³ combine to form:

An example includes a compound of the following structure:

Embodiments of the present invention include those compounds where R⁴ isH, optionally substituted C₁-C₆alkyl, or optionally substituted C₁-C₆alkoxyl, preferably H or optionally substituted C₁-C₆alkyl. In certainembodiments, R⁴ is optionally substituted C₁-C₆ alkyl. In embodimentswhere R4 is alkyl, it is preferably C₁-C₃alkyl, more preferably,C₁C₆alkyl, with methyl being even more preferred.

Embodiments of the present invention include those compounds where m is1, 2, 3, 4, or 5 when R¹ is attached via a nitrogen atom. In particular,m is 1, or m is 2, or m is 3, or m is 4, or m is 5, or m can be anycombination of the above including, 1 and 2; 1 and 3; 2 and 3; 1, 2, and3; etc. Other embodiments include those compounds where m is 0, 1, 2, 3,4, or 5 when R¹ is attached via a carbon atom. In particular, m is 0, orm is 1, or m is 2, or m is 3, or m is 4, or m is 5, or m can be anycombination of the above including, 0 and 1; 0 and 2; 0, 1, and 2; 1, 2,and 3; etc.

In certain preferred embodiments of the present invention, s is 2.

In other preferred embodiments of the present invention, R¹² is H,C₁-C₆alkyl, cycloalkyl, aryl, arylalkyl, or heteroaryl, more preferablyH or heteroaryl, with heteroaryl being even more preferred.Alternatively, C₁-C₆alkyl, aryl, arylalkyl, or heteroaryl is preferredin some embodiments.

In certain preferred embodiments of the present invention, R¹³, R¹⁴R^(13a), R^(13b), R^(13c), and R^(14a) are each independently H orC₁-C₆alkyl, more preferably wherein at least one of is R¹³, R¹⁴ R^(13a),R^(13b), R^(13c), and R^(14a) is C₁-C₆alkyl. In other alternativelypreferred embodiments, R^(13a) and R¹³ are each independently C₁-C₃alkyl; or R^(14a) and R¹⁴ are each independently C₁-C₃ alkyl.

In still other preferred embodiments of the present invention, R¹³ andR¹⁴, taken together with the carbon atoms through which they areconnected form a fused phenyl, thienyl, oxazolyl, pyridinyl, orC₃-C₆cycloalkyl ring; or R^(13b) and R¹⁴, or R¹³ and ^(14a), or R^(13b)and ^(14a), or R^(13c) and R^(14a), taken together with the carbon atomsthrough which they are connected form a fused C₃-C₆cycloalkyl ring; orR¹³ and R^(13a), or R¹⁴ and R^(14a), taken together with the carbon atomto which they are attached form a C₃-C₈cycloalkyl ring; provided that nomore than one pair of R¹³ and R¹⁴, R^(13b) and R¹⁴, R¹³ and R^(14a),R^(13b) and R^(14a), R^(13c) and R^(14a), R¹³ and R^(13a), and R¹⁴ andR^(14a) are taken together with the carbon atoms through which they areconnected or to which they are attached to form a ring; and wherein thefused phenyl, thienyl, pyrrolyl, oxazolyl, pyridinyl, or cycloalkyl ringis optionally substituted with 1 to 3 R²⁰ groups. More preferably, R¹³and R¹⁴, R^(13b) and R¹⁴, or R¹³ and ^(14a), or R^(13b) and ^(14a), orR^(13c) and R^(14a), taken together with the carbon atoms through whichthey are connected form a fused C₃-C₆cycloalkyl ring; or R¹³ andR^(13a), or R¹⁴ and R^(14a), taken together with the carbon atom towhich they are attached form a C₃-C₈cycloalkyl ring; then the cycloalkylring is a is C₃-C₄cycloalkyl ring.

In some preferred embodiments of the present invention, R¹⁴ isheteroaryl.

In some preferred embodiments of the present invention, R²⁰ is alkyl; inothers it is cycloalkyl, more preferably cyclobutyl. In still others,R²⁰ is F, Cl, CF₃, NR²³R²⁴, or C₁-C₆alkyl optionally substituted withOR²⁶, cycloalkylC₀-C₄alkyl, or heterocycloalkylC₀-C₄alkyl, morepreferably C₁-C₆alkyl optionally substituted with OR²⁶.

In certain other preferred embodiments of the present invention, R²¹ isH or C₁-C₆alkyl.

In some preferred embodiments of the present invention, R²³ and R²⁴ areeach independently C₁-C₆alkyl.

In yet other preferred embodiments of the present invention, R²⁶ is H orC₁-C₆alkyl.

In some preferred embodiments of the present invention, at least one ofX and X_(a) is CH, more preferably X and X_(a) are each CH.

Embodiments of the present invention include those compounds of formulaI wherein:

-   X and X^(a) are CH;-   Y is O;-   R¹ is NR¹⁰R¹¹ or a 5 to 6 membered heterocycloalkyl ring containing    1 or 2 nitrogen atoms and optionally substituted with 1 to 3 R²⁰    groups; or R¹ is NR¹⁰R¹¹, pyrrolidinyl or piperidyl, wherein the    pyrrolidinyl and piperidyl groups are optionally substituted with 1    to 3 R²⁰ groups; or R¹ is pyrrolidinyl or piperidyl, wherein the    pyrrolidinyl and piperidyl groups are optionally substituted with 1    to 3 R²⁰ groups;-   R² is

or

-   R² is

-   R³ at each occurrence is independently, H, F, Cl, Br, I, OR²¹,    NR²³R²⁴, NO₂, CN, CF₃, C₁-C₆ alkyl, C(═O)R²¹, CO₂R²¹, or    C(═O)NR²³R²⁴; or    -   when R³ is ortho to R², then R³ and R¹⁴ can combine to form        —CH₂CH₂—; or    -   R³ at each occurrence is independently, H; F; Cl; Br; I; OR²¹;        NR²³R²⁴; NO₂; CN; CF₃; C₁-C₆ alkyl; C(═O)R²¹; CO₂R²¹; or        C(═O)NR²³R²⁴;-   R⁴ is H or C₁-C₆ alkyl, wherein the alkyl group is optionally    substituted with 1 to 3 R²⁰ groups;-   R¹⁰ and R¹¹ are each, independently H or C₁-C₆ alkyl, wherein the    alkyl group is optionally substituted with 1 to 3 R²⁰ groups;-   R¹² is H, C₁-C₆ alkyl, phenyl, or benzyl, wherein the alkyl, phenyl    and benzyl groups are optionally substituted with 1 to 3 R²⁰ groups;-   R¹³ and R¹⁴ are independently H, C₁-C₆ alkyl, phenyl, or benzyl, or    R¹³ and R¹⁴ can combine to form a fused phenyl, thienyl, cyclopentyl    or cyclohexyl ring; wherein the phenyl, thienyl, pyrrolyl,    cyclopentyl or cyclohexyl rings are optionally substituted with 1 to    3 R²⁰ groups; or    -   R¹³ and R¹⁴ are independently H, C₁-C₆ alkyl, phenyl, or benzyl;        or    -   R¹³ and R¹⁴ can combine to form a fused phenyl, thienyl,        cyclopentyl or cyclohexyl ring;-   R²⁰ at each occurrence is independently, H, F, Cl, Br, I, OR²¹,    OR²², NR²³R²⁴, NHOH, NO₂, CN, CF₃, C₁-C₆ alkyl optionally    substituted with OR²⁶, C₂-C₆ alkenyl, C₂-C₆ alkynyl, C₃-C₇    cycloalkyl, 3-7 membered heterocycloalkyl, phenyl, 5 or 6 membered    heteroaryl, arylalkyl, (═O), C(═O)R²¹, CO₂R²¹, OC(═O)R²¹,    C(═O)NR²³R²⁴, NR²⁷C(═O)R²¹, NR²⁷C(═O)OR²¹, OC(═O)NR²³R²⁴,    NR²⁷C(═S)R²¹, or S(O)_(q)R²¹;-   R²¹ at each occurrence is independently H, C₁-C₆ alkyl, aryl, or    arylalkyl;-   R²² at each occurrence is independently the residue of an amino acid    after the hydroxyl group of the carboxyl group is removed;-   R²³ and R²⁴ at each occurrence are each independently selected from    H, C₁-C₆ alkyl, and aryl, or R²³ and R²⁴, together with the nitrogen    atom to which they are attached, form a 3 to 7 membered heterocyclic    ring optionally substituted with ═O;-   R²⁶ is H, C₁-C₆ alkyl, aryl, or alkylaryl;-   R²⁷ is H or C₁-C₆ alkyl;-   m is 3 when R¹ is attached via a nitrogen atom, and m is 0 or 1 when    R¹ is attached via a carbon atom;-   n is 0 or 1;-   q is 0, 1, or 2.

Embodiments of the present invention include those compounds of formulaI wherein:

-   X is N and X^(a) is N or CH; or X and X^(a) are each N; or X is N    and X^(a) is CH;-   Y is O;-   R¹ is NR¹⁰R¹¹ or a 5 to 6 membered heterocycloalkyl ring containing    1 or 2 nitrogen atoms and optionally substituted with 1 to 3 R²⁰    groups; or R¹ is NR¹⁰R¹¹, pyrrolidinyl or piperidyl, wherein the    pyrrolidinyl and piperidinyl groups are optionally substituted with    1 to 3 R²⁰ groups; or R¹ is pyrrolidinyl or piperidinyl, wherein the    pyrrolidinyl and piperidyl groups are optionally substituted with 1    to 3 R²⁰ groups;-   R² is

or

-   R² is

-   R³ at each occurrence is independently, H, F, Cl, Br, I, OR²¹,    NR²³R²⁴, NO₂, CN, CF₃, C₁-C₆ alkyl, C(═O)R²¹, CO₂R²¹, or    C(═O)NR²³R²⁴; or    -   when R³ is ortho to R², then R³ and R¹⁴ can combine to form        —CH₂CH₂—; or    -   R³ at each occurrence is independently, H; F; Cl; Br; I; OR²¹;        NR²³R²⁴; NO₂; CN; CF₃; C₁-C₆ alkyl; C(═O)R²¹; CO₂R²¹; or        C(═O)NR²³R²⁴;-   R⁴ is H or C₁-C₆ alkyl, wherein the alkyl group is optionally    substituted with 1 to 3 R²⁰ groups;-   R¹⁰ and R¹¹ are each, independently H or C₁-C₆ alkyl, wherein the    alkyl group is optionally substituted with 1 to 3 R²⁰ groups;-   R¹² is H, C₁-C₆ alkyl, phenyl, or benzyl, wherein the alkyl, phenyl    and benzyl groups are optionally substituted with 1 to 3 R²⁰ groups;-   R¹³ and R¹⁴ are independently H, C₁-C₆ alkyl, phenyl, or benzyl, or    R¹³ and R¹⁴ can combine to form a fused phenyl, thienyl, cyclopentyl    or cyclohexyl ring; wherein the phenyl, thienyl, pyrrolyl,    cyclopentyl or cyclohexyl rings are optionally substituted with 1 to    3 R²⁰ groups; or    -   R¹³ and R¹⁴ are independently H, C₁-C₆ alkyl, phenyl, or benzyl;        or    -   R¹³ and R¹⁴ can combine to form a fused phenyl, thienyl,        cyclopentyl or cyclohexyl ring;-   R²⁰ at each occurrence is independently, H, F, Cl, Br, I, OR²¹,    OR²², NR²³R²⁴, NHOH, NO₂, CN, CF₃, C₁-C₆ alkyl optionally    substituted with OR²⁶, C₂-C₆ alkenyl, C₂-C₆ alkynyl, C₃-C₇    cycloalkyl, 3-7 membered heterocycloalkyl, phenyl, 5 or 6 membered    heteroaryl, arylalkyl, (═O), C(═O)R²¹, CO₂R²¹, OC(═O)R²¹,    C(═O)NR²³R²⁴, NR²⁷C(═O)R²¹, NR²⁷C(═O)OR²¹, OC(═O)NR²³R²⁴,    NR²⁷C(═S)R²¹, or S(O)_(q)R²¹;-   R²¹ at each occurrence is independently H, C₁-C₆ alkyl, aryl, or    arylalkyl;-   R²² at each occurrence is independently the residue of an amino acid    after the hydroxyl group of the carboxyl group is removed;-   R²³ and R²⁴ at each occurrence are each independently selected from    H, C₁-C₆ alkyl, and aryl, or R²³ and R²⁴, together with the nitrogen    atom to which they are attached, form a 3 to 7 membered heterocyclic    ring optionally substituted with ═O;-   R²⁶ is H, C₁-C₆ alkyl, aryl, or alkylaryl;-   R²⁷ is H or C₁-C₆ alkyl;-   m is 3 when R¹ is attached via a nitrogen atom, and m is 0 or 1 when    R¹ is attached via a carbon atom;-   n is 0 or 1;-   q is 0, 1, or 2.

Embodiments of the present invention include those compounds of formulaI wherein:

-   -   X and X^(a) are CH;    -   Y is O;    -   R¹ is NR¹⁰R¹¹, pyrrolidinyl or piperidyl, wherein the        pyrrolidinyl and piperidyl groups are optionally substituted        with 1 to 3 R²⁰ groups;    -   R² is para to the Y—(CHR⁴)_(m)—R¹ group;    -   R³ at each occurrence is independently, H, F, Cl, Br, I, OR²¹,        NR²³R²⁴, NO₂, CN, CF₃, C₁-C₆ alkyl, C(═O)R²¹, CO₂R²¹, or        C(═O)NR²³R²⁴; or    -   when R³ is ortho to R², then R³ and R¹⁴ can combine to form        —CH₂CH₂—;    -   m is 3 when R¹ is attached via a nitrogen atom, and m is 0 or 1        when R¹ is attached via a carbon atom;    -   n is 0 or 1.        In particular, a first embodiment includes those compounds        wherein:    -   R¹ is attached by the nitrogen atom;        R² is:

and

-   -   R¹³ and R¹⁴ combine to form a fused phenyl or thienyl ring; and    -   m is 3.        In other embodiments, R² is:

In further embodiments, R² is:

In a second particular embodiment:

-   -   R¹ is attached by the nitrogen atom;    -   R² is:

-   -   R¹³ and R¹⁴ combine to form a fused cyclopentyl or cyclohexyl        ring; and    -   m is 3.        In a third particular embodiment:    -   R¹ is attached by the nitrogen atom;    -   R² is:

-   -   R¹³ and R¹⁴ are independently H, C₁-C₆ alkyl, phenyl, or benzyl;        and    -   m is 3.        In a fourth particular embodiment:    -   R¹ is pyrrolidinyl or piperidyl, wherein the pyrrolidinyl and        piperidyl groups are attached by a ring carbon atom and each are        optionally substituted with 1 to 3 R²⁰ groups;    -   R² is:

-   -   R⁴ is H;    -   R¹³ and R¹⁴ are independently H, C₁-C₆ alkyl, phenyl, or benzyl;    -   m is 0 or 1.        In a fifth particular embodiment:    -   R¹ is attached by the nitrogen atom;    -   R² is:

-   -   R¹³ and R¹⁴ are independently H, C₁-C₆ alkyl, phenyl, or benzyl;    -   m is 3.        In a sixth particular embodiment:    -   R¹ is attached by the nitrogen atom;    -   R² is:

-   -   R¹³ and R¹⁴ are independently H, C₁-C₆ alkyl, phenyl, or benzyl;    -   m is 3.        In a seventh particular embodiment:    -   R¹ is attached by the nitrogen atom;    -   R² is ortho to R³, and R² is:

-   -   R³ and R¹⁴ combine to form —CH₂CH₂—;    -   m is 3.

Embodiments of the present invention include those compounds of formulaI wherein:

-   X and X^(a) are CH;-   Y is O;-   R¹ is NR¹⁰R¹¹, pyrrolidinyl or piperidyl, wherein the pyrrolidinyl    and piperidyl groups are optionally substituted with 1 to 3 R²⁰    groups;-   R² is para to the Y—(CHR⁴)_(m)—R¹ group;-   R³ at each occurrence is independently, H, F, Cl, Br, I, OR²¹,    NR²³R²⁴, NO₂, CN, CF₃, C₁-C₆ alkyl, C(═O)R²¹, CO₂R²¹, or    C(═O)NR²³R²⁴; or    -   when R³ is ortho to R², then R³ and R¹⁴ can combine to form        —CH₂CH₂—;-   m is 3 when R¹ is attached via a nitrogen atom, and m is 0 or 1 when    R¹ is attached via a carbon atom;-   n is 0 or 1.

Additional aspects of the present invention include compounds of formulaII which incorporate the embodiments described above for compounds offormula I, as is appropriate. For example, additional embodimentsinclude compound of formula II with the preferred moieties of groups R¹;or R¹ and R¹³; or R¹, R²³ and R²⁴, etc.

For example, in certain embodiments of compounds of formula II:

R¹ is NR¹⁰R¹¹, pyrrolidinyl or piperidyl, wherein the pyrrolidinyl andpiperidyl groups are optionally substituted with 1 to 3 R²⁰ groups.

For example, in other embodiments of compounds of formula II:

-   R³ at each occurrence is independently, H, F, Cl, Br, I, OR²¹,    NR²³R²⁴, NO₂, CN, CF₃, C₁-C₆ alkyl, C(═O)R²¹, CO₂R²¹, or    C(═O)NR²³R²⁴; or-   when R³ is ortho to R², then R³ and R¹⁴ can combine to form    —CH₂CH₂—.

In certain embodiments, the compounds of the formula I*:

are selected from the group consisting of:

-   2-methyl-6-{4-[(R)-2-methyl-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-[4-(1-cyclopentyl-piperidin-4-yloxy)-phenyl]-2-methyl-2H-pyridazin-3-one;-   6-{3,5-difluoro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-methyl-2H-pyridazin-3-one;-   6-{3-chloro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-methyl-2H-pyridazin-3-one;-   2,6-dimethyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   2,6-dimethyl-5-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   6-methyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-methyl-5-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   5-[4-(3-azepan-1-yl-propoxy)-phenyl]-6-methyl-2H-pyridazin-3-one;-   2-methyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   2-methyl-5-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   5-[4-(3-azepan-1-yl-propoxy)-phenyl]-2-methyl-2H-pyridazin-3-one;-   5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyridin-2-yl-2H-pyridazin-3-one;-   5-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2-pyridin-2-yl-2H-pyridazin-3-one;-   5-[4-(3-azepan-1-yl-propoxy)-phenyl]-2-pyridin-2-yl-2H-pyridazin-3-one;-   2-methyl-5-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   2-(6-methyl-pyridin-2-yl)-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   2-(3-methyl-pyridin-2-yl)-5-{4-[3-((R)-2-methylpyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-methyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyridin-2-yl-2H-pyridazin-3-one;-   6-methyl-2-(3-methyl-pyridin-2-yl)-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-methyl-5-[4-(piperidin-4-yloxy)-phenyl]-2H-pyridazin-3-one;    hydrochloride;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-6-methyl-2H-pyridazin-3-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-6-methyl-2-pyridin-2-yl-2H-pyridazin-3-one;-   5-[4-(piperidin-4-yloxy)-phenyl]-2H-pyridazin-3-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-2H-pyridazin-3-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-6-methyl-2-thiophen-3-yl-2H-pyridazin-3-one;-   6-methyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-thiophen-3-yl-2H-pyridazin-3-one;-   5-{4-[3-((S)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyridin-2-yl-2H-pyridazin-3-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-6-methyl-4,5-dihydro-2H-pyridazin-3-one;-   6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one;-   6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5-pyridin-2-yl-2H-pyridazin-3-one;-   6-[4-(piperidin-4-yloxy)-phenyl]-5-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-5-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-5-pyridin-2-yl-2H-pyridazin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-4-methyl-4,5-dihydro-2H-pyridazin-3-one;-   5-[6-(1-cyclobutyl-piperidin-4-yloxy)-pyridin-3-yl]-2H-pyridazin-3-one;-   2-(2-fluoro-ethyl)-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-{3-fluoro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-[3-fluoro-4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   4-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one;-   4-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   4-methyl-6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   4-{4-[3-((S)-2-hydroxymethyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-methyl-5,6,7,8-tetrahydro-2H-phthalazin-1-one;-   2-methyl-4-{3-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2,5,6,7-tetrahydro-cyclopenta[d]pyridazin-1-one;-   2-methyl-4-[3-(3-piperidin-1-yl-propoxy)-phenyl]-2,5,6,7-tetrahydro-cyclopenta[d]pyridazin-1-one;-   4-{3-[3-((S)-2-hydroxymethyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-methyl-2,5,6,7-tetrahydro-cyclopenta[d]pyridazin-1-one;-   2-isopropyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   2-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-5-(6-oxo-1,6-dihydro-pyridazin-3-yl)-benzonitrile;-   2-[3-(piperidin-1-yl)-propoxy]-5-(6-oxo-1,6-dihydro-pyridazin-3-yl)-benzonitrile;-   2-(2-hydroxyethyl)-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-{4-[(S)-2-methyl-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   4-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2,5,6,7-tetrahydro-cyclopenta[d]pyridazin-1-one;-   6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   6-[3-methoxy-4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   6-{3-methoxy-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-[2-methyl-4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyrimidin-2-yl-2H-pyridazin-3-one;-   6-[6-(1-cyclopentyl-piperidin-4-yloxy)-pyridin-3-yl]-2H-pyridazin-3-one;-   6-[6-(1-isopropyl-piperidin-4-ylmethoxy)-pyridin-3-yl]-2H-pyridazin-3-one;-   6-[6-(1-cyclobutyl-piperidin-4-yloxy)-pyridin-3-yl]-2H-pyridazin-3-one;-   6-[6-(1-isopropyl-piperidin-4-yloxy)-pyridin-3-yl]-2H-pyridazin-3-one;-   6-[6-(1-cyclopentyl-piperidin-4-yloxy)-pyridin-3-yl]-2-methyl-2H-pyridazin-3-one;-   6-[6-(1-cyclobutyl-piperidin-4-yloxy)-pyridin-3-yl]-2-methyl-2H-pyridazin-3-one;-   6-[6-(1-cyclobutyl-piperidin-4-yloxy)-pyridin-3-yl]-2-isopropyl-2H-pyridazin-3-one;-   6-{6-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-pyridin-3-yl}-2H-pyridazin-3-one;-   6-[6-(3-piperidin-1-yl-propoxy)-pyridin-3-yl]-2H-pyridazin-3-one;-   6-[6-(1-cyclobutyl-piperidin-4-yloxy)-pyridin-3-yl]-4,4-dimethyl-4,5-dihydro-2H-pyridazin-3-one;-   6-[6-(1-cyclobutyl-piperidin-4-yloxy)-pyridin-3-yl]-2-pyridin-2-yl-2H-pyridazin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-3-fluoro-phenyl]-4,5-dihydro-2H-pyridazin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-4,4-dimethyl-4,5-dihydro-2H-pyridazin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-3-fluoro-phenyl]-4,4-dimethyl-4,5-dihydro-2H-pyridazin-3-one;-   6-[4-(1-cyclopentyl-piperidin-4-yloxy)-phenyl]-2H-pyridazin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-2H-pyridazin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-3-fluoro-phenyl]-2H-pyridazin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-2-pyridin-2-yl-2H-pyridazin-3-one;-   6-[4-(piperidin-4-yloxy)-phenyl]-2-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one;-   6-[4-((R)-1-cyclohexyl-pyrrolidin-3-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one;-   6-[4-((R)-1-cyclohexyl-pyrrolidin-3-yloxy)-phenyl]-2H-pyridazin-3-one;-   6-[4-((R)-1-cyclobutyl-pyrrolidin-3-yloxy)-phenyl]-2H-pyridazin-3-one;-   6-[4-((R)-1-cyclopentyl-pyrrolidin-3-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one;-   2-cyclobutyl-6-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one;-   2-cyclobutyl-6-[4-(1-cyclopentyl-piperidin-4-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one;-   2-cyclobutyl-6-[4-(piperidin-4-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-2-(2,2,2-trifluoro-ethyl)-4,5-dihydro-2H-pyridazin-3-one;-   6-[4-(1-cyclopentyl-piperidin-4-yloxy)-phenyl]-2-(2,2,2-trifluoro-ethyl)-4,5-dihydro-2H-pyridazin-3-one;-   6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-(2,2,2-trifluoro-ethyl)-4,5-dihydro-2H-pyridazin-3-one;-   6-{4-[3-piperidin-1-yl-propoxy]-phenyl}-2-(2,2,2-trifluoro-ethyl)-4,5-dihydro-2H-pyridazin-3-one;-   6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-(2,2,2-trifluoro-ethyl)-2H-pyridazin-3-one;-   6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2-(2,2,2-trifluoro-ethyl)-2H-pyridazin-3-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.2.0]oct-4-en-2-one;-   5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.2.0]oct-4-en-2-one;-   4-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-2,4a,5,6,7,7a-hexahydro-cyclopenta[d]pyridazin-1-one;-   4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2,4a,5,6,7,7a-hexahydro-cyclopenta[d]pyridazin-1-one;-   4-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-2,5,6,7-tetrahydro-cyclopenta[d]pyridazin-1-one;-   2-cyclobutyl-6-[6-(1-cyclobutyl-piperidin-4-yloxy)-pyridin-3-yl]-4,5-dihydro-2H-pyridazin-3-one;-   6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one;-   4,4-dimethyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one;-   6-{3-fluoro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one;-   6-[3-fluoro-4-(3-piperidin-1-yl-propoxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one;-   5,5-dimethyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one;-   6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one;-   6-{3,5-difluoro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-{3,5-dibromo-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-{3,5-difluoro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-3,5-difluoro-phenyl]-4,5-dihydro-2H-pyridazin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-3,5-difluoro-phenyl]-2H-pyridazin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-5-methyl-4,5-dihydro-2H-pyridazin-3-one;-   (R)-6-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-5-methyl-4,5-dihydro-2H-pyridazin-3-one;-   (S)-6-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-5-methyl-4,5-dihydro-2H-pyridazin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-5-ethyl-4,5-dihydro-2H-pyridazin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-5-methyl-2-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one;-   5-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one    racemate;-   5-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one    diastereomer;-   5-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one    diastereomer;-   5-methyl-6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one;-   5-methyl-6-[4-(3-pyrrolidin-1-yl-propoxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one;-   6-{(R)-2-methyl-4-[3-(2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one;-   2-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-6-phenyl-2H-pyridazin-3-one;-   6-methyl-2-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   2-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-phthalazin-1-one;-   2-[6-(1-cyclobutyl-piperidin-4-yloxy)-pyridin-3-yl]-6-phenyl-2H-pyridazin-3-one;-   2-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-6-pyridin-3-yl-2H-pyridazin-3-one;-   4-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3-methyl-6H-isoxazolo[3,4-d]pyridazin-7-one;-   3-methyl-4-[4-(piperidin-4-yloxy)-phenyl]-6H-isoxazolo[3,4-d]pyridazin-7-one;-   3-methyl-4-[4-(3-piperidin-1-yl-propoxy)-phenyl]-6H-isoxazolo[3,4-d]pyridazin-7-one;-   3-methyl-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-6H-isoxazolo[3,4-d]pyridazin-7-one;-   8-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-5,6-dihydro-2H-benzo[h]cinnolin-3-one;-   5-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   5-ethyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   8-[3-(2-methyl-pyrrolidin-1-yl)-propoxy]-4,4a,5,6-tetrahydro-2H-benzo[h]cinnolin-3-one;-   6-{2-methoxy-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-{2-fluoro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyridin-2-yl-2H-pyridazin-3-one;-   6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one;-   6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4-pyridin-2-yl-2H-pyridazin-3-one;-   8-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-5,6-dihydro-3H-benzo[f]cinnolin-2-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-2-fluoro-phenyl]-4,5-dihydro-2H-pyridazin-3-one;-   8-(1-cyclobutyl-piperidin-4-yloxy)-4,4a,5,6-tetrahydro-2H-benzo[h]cinnolin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-2-fluoro-phenyl]-2H-pyridazin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-5-methyl-2H-pyridazin-3-one;-   5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   2-methoxymethyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   5-{4-[(S)-2-methyl-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   5-{4-[(R)-2-methyl-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   5-[4-((S)-2-methyl-3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   5-[4-((R)-2-methyl-3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   5-{3,5-dibromo-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   2-methoxymethyl-5-{2-methyl-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   5-{2-methyl-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   2-methoxymethyl-5-[2-methyl-4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   5-[2-methyl-4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-2-methyl-phenyl]-2-methoxymethyl-2H-pyridazin-3-one;-   4-methoxy-2-methoxymethyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   5-methoxy-2-methoxymethyl-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   5-methoxy-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-[4-(3-morpholin-4-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   6-{4-[3-((S)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-[4-(3-pyrrolidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   6-{4-[3-(cyclobutyl-methyl-amino)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-{4-[3-(cyclopentyl-methyl-amino)-propoxy]-phenyl}-2H-pyridazin-3-one;-   5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-{4-[(S)-2-methyl-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one    single isomer;-   5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one    single isomer;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one    single isomer;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one    single isomer;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3-ethyl-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3-isopropyl-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3-methyl-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3-(4-fluoro-phenyl)-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3-(2,2,2-trifluoro-ethyl)-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   6-[4-(2-hydroxy-3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   6-{4-[2-hydroxy-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-{4-[(S)-2-hydroxy-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-{4-[(R)-2-hydroxy-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-[4-((R)-2-hydroxy-3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   5-[4-(1-cyclopentyl-piperidin-4-yloxy)-phenyl]-3-methyl-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-[4-(1-cyclopentyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;    and-   6-cyclopropyl-2-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;

or a stereoisomeric form, mixture of stereoisomeric forms, or apharmaceutically acceptable salt thereof.

More preferably, they are selected from the group consisting of:

-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-6-methyl-2H-pyridazin-3-one;-   6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-4,4-dimethyl-4,5-dihydro-2H-pyridazin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-yloxy)-3-fluoro-phenyl]-4,4-dimethyl-4,5-dihydro-2H-pyridazin-3-one;-   6-[6-(1-cyclobutyl-piperidin-4-yloxy)-pyridin-3-yl]-4,4-dimethyl-4,5-dihydro-2H-pyridazin-3-one;-   5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyridin-2-yl-2H-pyridazin-3-one;-   5-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2-pyridin-2-yl-2H-pyridazin-3-one;-   6-{4-[(S)-2-Methyl-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   4,4-dimethyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one;-   5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-{4-[(S)-2-methyl-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.2.0]oct-4-en-2-one;-   5-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one    one diastereomer;-   5-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one    one diastereomer;-   5-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one;    and-   6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;

or a stereoisomeric form, mixture of stereoisomeric forms, or apharmaceutically acceptable salt thereof.

Still more preferably, they are selected from the group consisting of:

-   5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyridin-2-yl-2H-pyridazin-3-one;-   5-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2-pyridin-2-yl-2H-pyridazin-3-one;-   6-{4-[(S)-2-methyl-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   4,4-dimethyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one;-   5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-;[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-{4-[(S)-2-methyl-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.2.0]oct-4-en-2-one;-   5-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one    one diastereomer;-   5-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one    one diastereomer;-   5-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one;    and-   6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;

or a stereoisomeric form, mixture of stereoisomeric forms, or apharmaceutically acceptable salt thereof.

Even more preferably, they are selected from the group consisting of:

-   4,4-dimethyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one;-   5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-{4-[(S)-2-methyl-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one;-   5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.2.0]oct-4-en-2-one;-   5-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one    one diastereomer;-   5-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one    one diastereomer;-   5-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one;    and-   6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;

or a stereoisomeric form, mixture of stereoisomeric forms, or apharmaceutically acceptable salt thereof; with the compound6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one,or a stereoisomeric form, mixture of stereoisomeric forms, or apharmaceutically acceptable salt thereof being most preferred.

In certain alternatively preferred embodiments, the compounds of formulaI are selected from the group consisting of:

-   2-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   2-methyl-6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   2-isopropyl-6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   2-isopropyl-6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one;-   2-isopropyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   2-ethyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-{3-fluoro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-methyl-2H-pyridazin-3-one;-   2-(2,4-dichloro-benzyl)-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one;-   2-(3,5-dichloro-phenyl)-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-[3-fluoro-4-(3-piperidin-1-yl-propoxy)-phenyl]-2-phenyl-2H-pyridazin-3-one;-   6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2,5,6,7-tetrahydro-cyclopenta[d]pyridazin-1-one;-   2-methyl-6-{4-[(S)-2-methyl-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-{4-[3-((S)-2-hydroxymethyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-methyl-2H-pyridazin-3-one;-   6-{4-[3-((R)-2-hydroxymethyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-methyl-2H-pyridazin-3-one;-   2-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one;-   2-benzyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one;-   2-benzyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-phenyl-2H-pyridazin-3-one;-   6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-phenyl-2H-pyridazin-3-one;-   2-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   5-Isopropyl-7-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5H-thieno[2,3-d]pyridazin-4-one;-   7-{4-[3-(2,5-dimethyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5-isopropyl-5H-thieno[2,3-d]pyridazin-4-one;-   5-isopropyl-7-[4-(3-piperidin-1-yl-propoxy)-phenyl]-5H-thieno[2,3-d]pyridazin-4-one;-   7-{4-[3-(3,3-dimethyl-piperidin-1-yl)-propoxy]-phenyl}-5-isopropyl-5H-thieno[2,3-d]pyridazin-4-one;-   5-isopropyl-7-{4-[3-((S)-2-methoxymethyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5H-thieno[2,3-d]pyridazin-4-one;-   5-isopropyl-7-{4-[3-((R)-2-methoxymethyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5H-thieno[2,3-d]pyridazin-4-one;-   7-[4-(3-diethylamino-propoxy)-phenyl]-5-isopropyl-5H-thieno[2,3-d]pyridazin-4-one;-   5-isopropyl-7-[4-(3-pyrrolidin-1-yl-propoxy)-phenyl]-5H-thieno[2,3-d]-pyridazin-4-one;-   5-isopropyl-7-{4-[3-(4-pyrrolidin-1-yl-piperidin-1-yl)-propoxy]-phenyl}-5H-thieno[2,3-d]pyridazin-4-one;-   7-{4-[3-((2R,5R)-2,5-dimethyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5-isopropyl-5H-thieno[2,3-d]pyridazin-4-one;-   7-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5-propyl-5H-thieno[2,3-d]pyridazin-4-one;-   7-{4-[3-((2R,5R)-2,5-dimethyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5-propyl-5H-thieno[2,3-d]pyridazin-4-one;-   7-{4-[3-(4-methyl-piperidin-1-yl)-propoxy]-phenyl}-5-propyl-5H-thieno[2,3-d]pyridazin-4-one;-   7-{4-[3-(4-dimethylamino-piperidin-1-yl)-propoxy]-phenyl}-5-propyl-5H-thieno[2,3-d]pyridazin-4-one;-   5-propyl-7-{4-[3-((S)-2-pyrrolidin-1-ylmethyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5H-thieno[2,3-d]pyridazin-4-one;-   5-(4-chloro-benzyl)-7-[4-(3-piperidin-1-yl-propoxy)-phenyl]-5H-thieno[2,3-d]pyridazin-4-one;-   5-(4-chloro-benzyl)-7-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5H-thieno[2,3-d]pyridazin-4-one;-   2,4-dimethyl-6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   2,4-dimethyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   2-isopropyl-4-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   2-isopropyl-4-methyl-6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   2-benzyl-4-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   2-benzyl-4-methyl-6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   4-benzyl-2-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;-   4-benzyl-2-methyl-6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   2-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5-phenyl-2H-pyridazin-3-one;-   2-methyl-5-phenyl-6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;-   2-methyl-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-phthalazin-1-one;-   2-methyl-4-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-phthalazin-1-one;-   2-methyl-4-[4-(2-piperidin-1-yl-ethoxy)-phenyl]-2H-phthalazin-1-one;-   2-methyl-4-[4-(3-pyrrolidin-1-yl-propoxy)-phenyl]-2H-phthalazin-1-one;-   4-[4-(3-azepan-1-yl-propoxy)-phenyl]-2-methyl-2H-phthalazin-1-one;-   2-(4-chloro-benzyl)-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-phthalazin-1-one;-   2-(4-chloro-benzyl)-4-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-phthalazin-1-one;-   2-methyl-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2,5,6,7-tetrahydro-cyclopenta[d]pyridazin-1-one;-   2-methyl-4-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2,5,6,7-tetrahydro-cyclopenta[d]pyridazin-1-one;-   2-methyl-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2,4a,5,6,7,7a-hexahydro-cyclopenta[d]pyridazin-1-one;-   2-methyl-4-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2,4a,5,6,7,7a-hexahydro-cyclopenta[d]pyridazin-1-one;-   2-methyl-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5,6,7,8-tetrahydro-2H-phthalazin-1-one;-   4-{4-[3-(butyl-ethyl-amino)-propoxy]-phenyl}-2-methyl-5,6,7,8-tetrahydro-2H-phthalazin-1-one;-   4-[4-(3-methyl-4-oxo-3,4-dihydro-phthalazin-1-yl)-phenoxymethyl]-piperidine-1-carboxylic    acid tert-butyl ester;-   2-methyl-4-[4-(piperidin-4-ylmethoxy)-phenyl]-2H-phthalazin-1-one;-   4-[4-(1-cyclobutyl-piperidin-4-ylmethoxy)-phenyl]-2-methyl-2H-phthalazin-1-one;-   4-[4-(1-methyl-6-oxo-1,6-dihydro-pyridazin-3-yl)-phenoxymethyl]-piperidine-1-carboxylic    acid tert-butyl ester;-   2-methyl-6-[4-(piperidin-4-ylmethoxy)-phenyl]-2H-pyridazin-3-one;-   6-[4-(1-cyclobutyl-piperidin-4-ylmethoxy)-phenyl]-2-methyl-2H-pyridazin-3-one;-   6-[4-(1-isopropyl-piperidin-4-ylmethoxy)-phenyl]-2-methyl-2H-pyridazin-3-one;-   6-[4-(1-cyclopropylmethyl-piperidin-4-ylmethoxy)-phenyl]-2-methyl-2H-pyridazin-3-one;-   6-[4-(1-cyclopentyl-piperidin-4-ylmethoxy)-phenyl]-2-methyl-2H-pyridazin-3-one;-   2-methyl-6-[4-(1-methyl-piperidin-4-ylmethoxy)-phenyl]-2H-pyridazin-3-one;-   6-[4-(1-isopropyl-piperidin-4-yloxy)-phenyl]-2-methyl-2H-pyridazin-3-one;-   2-methyl-6-[4-(piperidin-4-yloxy)-phenyl]-2H-pyridazin-3-one;-   2-methyl-6-[4-(piperidin-4-yloxy)-phenyl]-2H-pyridazin-3-one;-   2-methyl-8-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-5,6-dihydro-2H-benzo[h]cinnolin-3-one;-   8-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-2-phenyl-5,6-dihydro-2H-benzo[h]cinnolin-3-one;-   2-benzyl-8-(3-piperidin-1-yl-propoxy)-5,6-dihydro-2H-benzo[h]cinnolin-3-one;-   2-isopropyl-8-(3-piperidin-1-yl-propoxy)-5,6-dihydro-2H-benzo[h]cinnolin-3-one;-   2-methyl-7-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-2H-phthalazin-1-one;-   2-methyl-7-(3-piperidin-1-yl-propoxy)-2H-phthalazin-1-one; and-   6-{3-fluoro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-phenyl-2H-pyridazin-3-one;    and stereoisomeric forms, mixtures of stereoisomeric forms or    pharmaceutically acceptable salt forms thereof; with the compound    6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one,    or a stereoisomeric form, mixture of stereoisomeric forms, or a    pharmaceutically acceptable salt thereof being more preferred.

In a second embodiment, the compounds of formula I are selected fromExamples 22 to 38, 49 to 50 and 52 to 55. In a third embodiment, thecompounds are selected from Examples 12, and 56 to 61. In a fourthembodiment, the compounds are selected from Examples 1 to 3, 5 to 7, 9to 11, 13 to 15, 18, 20, 39 to 48, and 81. In a fifth embodiment, thecompounds are selected from Examples 51, and 62 to 74. In a sixthembodiment, the compounds are selected from Examples 4, 8, 16 to 17, and19. In a seventh embodiment, the compounds are selected from Examples 75to 78. In a eighth embodiment, the compounds are Examples 79 and 80.

In another aspect, the present invention is directed to pharmaceuticallyacceptable salts of the compounds described above. As used herein,“pharmaceutically acceptable salts” includes salts of compounds of thepresent invention derived from the combination of such compounds withnon-toxic acid or base addition salts.

Acid addition salts include inorganic acids such as hydrochloric,hydrobromic, hydroiodic, sulfuric, nitric and phosphoric acid, as wellas organic acids such as acetic, citric, propionic, tartaric, glutamic,salicylic, oxalic, methanesulfonic, para-toluenesulfonic, succinic, andbenzoic acid, and related inorganic and organic acids.

Base addition salts include those derived from inorganic bases such asammonium and alkali and alkaline earth metal hydroxides, carbonates,bicarbonates, and the like, as well as salts derived from basic organicamines such as aliphatic and aromatic amines, aliphatic diamines,hydroxy alkamines, and the like. Such bases useful in preparing thesalts of this invention thus include ammonium hydroxide, potassiumcarbonate, sodium bicarbonate, calcium hydroxide, methylamine,diethylamine, ethylenediamine, cyclohexylamine, ethanolamine and thelike.

In addition to pharmaceutically-acceptable salts, other salts areincluded in the invention. They may serve as intermediates in thepurification of the compounds, in the preparation of other salts, or inthe identification and characterization of the compounds orintermediates.

The pharmaceutically acceptable salts of compounds of the presentinvention can also exist as various solvates, such as with water,methanol, ethanol, dimethylformamide, ethyl acetate and the like.Mixtures of such solvates can also be prepared. The source of suchsolvate can be from the solvent of crystallization, inherent in thesolvent of preparation or crystallization, or adventitious to suchsolvent. Such solvates are within the scope of the present invention.

The present invention also encompasses the pharmaceutically acceptableprodrugs of the compounds disclosed herein. As used herein, “prodrug” isintended to include any compounds which are converted by metabolicprocesses within the body of a subject to an active agent that has aformula within the scope of the present invention. Since prodrugs areknown to enhance numerous desirable qualities of pharmaceuticals (e.g.,solubility, bioavailability, manufacturing, etc.) the compounds of thepresent invention may be delivered in prodrug form. Conventionalprocedures for the selection and preparation of suitable prodrugderivatives are described, for example, in Prodrugs, Sloane, K. B., Ed.;Marcel Dekker New York, 1992, incorporated by reference herein in itsentirety

It is recognized that compounds of the present invention may exist invarious stereoisomeric forms. As such, the compounds of the presentinvention include both diastereomers and enantiomers. The compounds arenormally prepared as racemates and can conveniently be used as such, butindividual enantiomers can be isolated or synthesized by conventionaltechniques if so desired. Such racemates and individual enantiomers andmixtures thereof form part of the present invention.

It is well known in the art how to prepare and isolate such opticallyactive forms. Specific stereoisomers can be prepared by stereospecificsynthesis using enantiomerically pure or enantiomerically enrichedstarting materials. The specific stereoisomers of either startingmaterials or products can be resolved and recovered by techniques knownin the art, such as resolution of racemic forms, normal, reverse-phase,and chiral chromatography, recrystallization, enzymatic resolution, orfractional recrystallization of addition salts formed by reagents usedfor that purpose. Useful methods of resolving and recovering specificstereoisomers described in Eliel, E. L.; Wilen, S. H. Stereochemistry ofOrganic Compounds; Wiley: New York, 1994, and Jacques, J, et al.Enantiomers, Racemates, and Resolutions; Wiley: New York, 1981, eachincorporated by reference herein in their entireties.

It is further recognized that functional groups present on the compoundsof Formula I may contain protecting groups. For example, the amino acidside chain substituents of the compounds of Formula I can be substitutedwith protecting groups such as benzyloxycarbonyl or t-butoxycarbonylgroups. Protecting groups are known per se as chemical functional groupsthat can be selectively appended to and removed from functionalities,such as hydroxyl groups and carboxyl groups. These groups are present ina chemical compound to render such functionality inert to chemicalreaction conditions to which the compound is exposed. Any of a varietyof protecting groups may be employed with the present invention.Preferred groups for protecting lactams include silyl groups such ast-butyldimethylsilyl (“TBDMS”), dimethoxybenzhydryl (“DMB”), acyl,benzyl (“Bn”), and methoxybenzyl groups. Preferred groups for protectinghydroxy groups include TBS, acyl, benzyl, benzyloxycarbonyl (“CBZ”),t-butyloxycarbonyl (“Boc”), and methoxymethyl. Many other standardprotecting groups employed by one skilled in the art can be found inGreene, T. W. and Wuts, P. G. M., “Protective Groups in OrganicSynthesis” 2d. Ed., Wiley & Sons, 1991.

For therapeutic purposes, the compounds of the present invention can beadministered by any means that results in the contact of the activeagent with the agent's site of action in the body of the subject. Thecompounds may be administered by any conventional means available foruse in conjunction with pharmaceuticals, either as individualtherapeutic agents or in combination with other therapeutic agents, suchas, for example, analgesics. The compounds employed in the methods ofthe present invention including, for example, the compounds of FormulaI, I*, I**, I(a-i), and/or II, may be administered by any means thatresults in the contact of the active agents with the agents' site orsite(s) of action in the body of a patient. The compounds of the presentinvention are preferably administered in therapeutically effectiveamounts for the treatment of the diseases and disorders described hereinto a subject in need thereof.

A therapeutically effective amount can be readily determined by theattending diagnostician, as one skilled in the art, by the use ofconventional techniques. The effective dose will vary depending upon anumber of factors, including the type and extent of progression of thedisease or disorder, the overall health status of the particularpatient, the relative biological efficacy of the compound selected, theformulation of the active agent with appropriate excipients, and theroute of administration. Typically, the compounds are administered atlower dosage levels, with a gradual increase until the desired effect isachieved.

Typical dose ranges are from about 0.01 mg/kg to about 100 mg/kg of bodyweight per day, with a preferred dose from about 0.01 mg/kg to 10 mg/kgof body weight per day. A preferred daily dose for adult humans includesabout 25, 50, 100 and 200 mg, and an equivalent dose in a human child.The compounds may be administered in one or more unit dose forms. Theunit dose ranges from about 1 to about 500 mg administered one to fourtimes a day, preferably from about 10 mg to about 300 mg, two times aday. In an alternate method of describing an effective dose, an oralunit dose is one that is necessary to achieve a blood serum level ofabout 0.05 to 20 μg/ml in a subject, and preferably about 1 to 20 μg/ml.

Although the compounds of the present invention may be administered asthe pure chemicals, it is preferable to present the active ingredient asa pharmaceutical composition.

Generally speaking, therapeutic compounds of this invention may beadministered to a patient alone or in combination with apharmaceutically acceptable carrier. Accordingly, the compounds of theinvention, for example, compounds of Formula I, I*, I**, I(a-i), and/orII, are preferably combined with a pharmaceutical carrier selected onthe basis of the chosen route of administration and standardpharmaceutical practice as described, for example, in Remington'sPharmaceutical Sciences (Mack Publishing Co., Easton, Pa., 1980), thedisclosures of which are hereby incorporated herein by reference, intheir entireties. The carrier(s) must be acceptable in the sense ofbeing compatible with the other ingredients of the composition and notdeleterious to the recipient thereof. The relative proportions of activeingredient and carrier may be determined, for example, by the solubilityand chemical nature of the compounds, chosen route of administration andstandard pharmaceutical practice.

The compounds of the present invention may be formulated intopharmaceutical compositions by admixture with one or morepharmaceutically acceptable excipients. The excipients are selected onthe basis of the chosen route of administration and standardpharmaceutical practice, as described, for example, in Remington: TheScience and Practice of Pharmacy, 20^(th) ed.; Gennaro, A. R., Ed.;Lippincott Williams & Wilkins: Philadelphia, Pa., 2000. The compositionsmay be formulated to control and/or delay the release of the activeagent(s), as in fast-dissolve, modified-release, or sustained-releaseformulations. Such controlled-release, or extended-release compositionsmay utilize, for example biocompatible, biodegradable lactide polymers,lactide/glycolide copolymers, polyoxyethylene-polyoxypropylenecopolymers, or other solid or semisolid polymeric matrices known in theart.

The compositions can be prepared for administration by oral means;parenteral means, including intravenous, intramuscular, and subcutaneousroutes; topical or transdermal means; transmucosal means, includingrectal, vaginal, sublingual and buccal routes; ophthalmic means; orinhalation means. Preferably the compositions are prepared for oraladministration, particularly in the form of tablets, capsules or syrups;for parenteral administration, particularly in the form of liquidsolutions, suspensions or emulsions; for intranasal administration,particularly in the form of powders, nasal drops, or aerosols; or fortopical administration, such as creams, ointments, solutions,suspensions aerosols, powders and the like.

For oral administration, the tablets, pills, powders, capsules, trochesand the like can contain one or more of the following: diluents orfillers such as starch, or cellulose; binders such as microcrystallinecellulose, gelatins, or polyvinylpyrrolidones; disintegrants such asstarch or cellulose derivatives; lubricants such as talc or magnesiumstearate; glidants such as colloidal silicon dioxide; sweetening agentssuch as sucrose or saccharin; or flavoring agents such as peppermint orcherry flavoring. Capsules may contain any of the afore listedexcipients, and may additionally contain a semi-solid or liquid carrier,such as a polyethylene glycol. The solid oral dosage forms may havecoatings of sugar, shellac, or enteric agents. Liquid preparations maybe in the form of aqueous or oily suspensions, solutions, emulsions,syrups, elixirs, etc., or may be presented as a dry product forreconstitution with water or other suitable vehicle before use. Suchliquid preparations may contain conventional additives such assurfactants, suspending agents, emulsifying agents, diluents, sweeteningand flavoring agents, dyes and preservatives.

The compositions may also be administered parenterally. Thepharmaceutical forms acceptable for injectable use include, for example,sterile aqueous solutions, or suspensions. Aqueous carriers includemixtures of alcohols and water, buffered media, and the like. Nonaqueoussolvents include alcohols and glycols, such as ethanol, and polyethyleneglycols; oils, such as vegetable oils; fatty acids and fatty acidesters, and the like. Other components can be added includingsurfactants; such as hydroxypropylcellulose; isotonic agents, such assodium chloride; fluid and nutrient replenishers; electrolytereplenishers; agents which control the release of the active compounds,such as aluminum monostearate, and various co-polymers; antibacterialagents, such as chlorobutanol, or phenol; buffers, and the like. Theparenteral preparations can be enclosed in ampules, disposable syringesor multiple dose vials. Other potentially useful parenteral deliverysystems for the active compounds include ethylene-vinyl acetatecopolymer particles, osmotic pumps, implantable infusion systems, andliposomes.

Other possible modes of administration include formulations forinhalation, which include such means as dry powder, aerosol, or drops.They may be aqueous solutions containing, for example,polyoxyethylene-9-lauryl ether, glycocholate and deoxycholate, or oilysolutions for administration in the form of nasal drops, or as a gel tobe applied intranasally. Formulations for topical use are in the form ofan ointment, cream, or gel. Typically these forms include a carrier,such as petrolatum, lanolin, stearyl alcohol, polyethylene glycols, ortheir combinations, and either an emulsifying agent, such as sodiumlauryl sulfate, or a gelling agent, such as tragacanth. Formulationssuitable for transdermal administration can be presented as discretepatches, as in a reservoir or microreservoir system, adhesivediffusion-controlled system or a matrix dispersion-type system.Formulations for buccal administration include, for example lozenges orpastilles and may also include a flavored base, such as sucrose oracacia, and other excipients such as glycocholate. Formulations suitablefor rectal administration are preferably presented as unit-dosesuppositories, with a solid based carrier, such as cocoa butter, and mayinclude a salicylate.

Pharmaceutical kits useful in, for example, the treatment of pain, whichcomprise a therapeutically effective amount of a compound of theinvention and/or other therapeutic compounds described herein, in one ormore sterile containers, are also within the ambit of the presentinvention. Sterilization of the container may be carried out usingconventional sterilization methodology well known to those skilled inthe art. The sterile containers of materials may comprise separatecontainers, or one or more multi-part containers, as exemplified by theUNIVIAL™ two-part container (available from Abbott Labs, Chicago, Ill.),as desired. The compound of the invention and/or other therapeuticcompound as described herein may be separate, or combined into a singledosage form as described above. Such kits may further include, ifdesired, one or more of various conventional pharmaceutical kitcomponents, such as for example, one or more pharmaceutically acceptablecarriers, additional vials for mixing the components, etc., as will bereadily apparent to those skilled in the art. Instructions, either asinserts or as labels, indicating quantities of the components to beadministered, guidelines for administration, and/or guidelines formixing the components, may also be included in the kit.

The compounds of the present invention may be used in methods to bindhistamine receptors, more preferably histamine H₃ receptors. Suchbinding may be accomplished by contacting the receptor with an effectiveamount of a compound of Formula I, I*, I**, I(a-i), and/or II. Thehistamine receptors may be located in the central nervous system orlocated peripherally to the central nervous system or in both locations.Preferably, the contacting step conducted in an aqueous medium,preferably at physiologically relevant ionic strength, pH, and the like.

In yet another aspect, the invention is directed to methods of bindinghistamine receptors, more preferably histamine H₃ receptors, comprisingthe step of administering to a patient in need thereof, an effectiveamount of a compound of the invention including, for example, a compoundof Formula I, I*, I**, I(a-i), and/or II, or any combination thereof.

In certain preferred aspects, the methods comprise the step ofadministering to said patient an therapeutically effective amount of acompound of Formula I, I*, I**, I(a-i), and/or II, or any combinationthereof.

In some preferred embodiments, the histamine receptors are H³ histaminereceptors. In certain more preferred embodiments, the compoundselectively binds H³ histamine receptors relative to H₁, H₂ and/or H₄receptors. In certain preferred embodiments, the H³ histamine receptorsare located in the central nervous system. In some other preferredembodiments, the compound of Formula I, I*, I**, I(a-i), and/or II, orany combination thereof exhibits activity toward the histaminereceptors. In certain preferred embodiments, the binding agonizes theactivity of the cannabinoid receptors. In other preferred embodiments,the binding antagonizes the activity of the cannabinoid receptors, morepreferably as a neutral antagonist. In still other preferredembodiments, the binding inversely agonizes the activity of thecannabinoid receptors.

In yet other preferred embodiments, the compounds of Formula I, I*, I**,I(a-i), and/or II, or any combination thereof exhibit activity towardthe histamine receptors in vivo. In alternatively preferred embodiments,the compounds of Formula I, I*, I**, I(a-i), and/or II, or anycombination thereof, exhibit activity toward the histamine receptors invitro.

In certain other preferred aspects of the invention, there are providedmethods of treating a disease, disorder or condition that may beaffected, modulated or controlled through the binding of histamine,preferably H₃ histamine receptors. More preferably these diseases,disorders, and/or conditions selected from the group consisting ofnarcolepsy or sleep/wake disorders, feeding behavior, eating disorders,obesity, cognition, arousal, memory, mood disorders, mood attentionalteration, attention deficit hyperactivity disorder (ADHD), Alzheimer'sdisease/dementia, schizophrenia, pain, stress, migraine, motionsickness, depression, psychiatric disorders, epilepsy, gastrointestinaldisorders, respiratory disorders, inflammation, and myocardialinfarction. The methods herein provided comprise administering to asubject in need of such treatment a therapeutically effective amount ofa compound of the invention, preferably a compound of formula:

more preferably a compound of formula I, I*, I**, I(a-i), and/or II, orany combination thereof.

In certain preferred embodiments, the disorder is narcolepsy orsleep/wake disorders. Alternatively the disorder treated is attentiondeficit hyperactivity disorder.

As those skilled in the art will appreciate, numerous modifications andvariations of the present invention are possible in light of the aboveteachings. It is therefore understood that within the scope of theappended claims, the invention may be practiced otherwise than asspecifically described herein, and the scope of the invention isintended to encompass all such variations.

Synthesis

The compounds of the present invention may be prepared in a number ofmethods well known to those skilled in the art, including, but notlimited to those described below, or through modifications of thesemethods by applying standard techniques known to those skilled in theart of organic synthesis. All processes disclosed in association withthe present invention are contemplated to be practiced on any scale,including milligram, gram, multigram, kilogram, multikilogram orcommercial industrial scale.

The general routes to prepare the examples shown herein are shown in theSchemes 1 and 2. The reagents and starting materials are commerciallyavailable, or readily synthesized by well-known techniques by one ofordinary skill in the arts. All substituents in the synthetic Schemes,unless otherwise indicated, are as previously defined.

Condensation of 4-(4-methoxyphenyl)-4-oxobutyric acid or ester, or aderivative there of, with hydrazine or an N-substituted hydrazinederivative in a solvent such as ethanol or 2-propanol provided a routeto 4,5-dihydropyridazinone intermediates. Keto-acid intermediates withsubstitution at the 4- and 5-position (Examples with R^(13/13a) andR^(14/14a)) may be readily prepared (Heterocycles, 2002, 57, 39; IndianJ. Chem, 1977, 16B, 631; Chem Pharm Bull, 1980, 42, 1850; J. Med. Chem.2003, 46, 2008). Pyridazinones with R^(13/13a) and R^(14/14a) fused withheteroaryl or cycloalkyl were readily prepared from the correspondinganhydrides. NH(N2) pyridazinones were alkylated with alkyl orsubstituted alkyl groups using an R¹²-halide, a base, for example K₂CO₃,Cs₂CO₃ or NaH, in an inert solvent such as DMF or CH₃CN.

In cases where R¹³ or R¹⁴ substituted 4,5-dihydropyridazinone formed amixture of isomers, the isomers were separated by standard methods knownin the art. Intermediates wherein R¹² is H may be converted to analogswherein R¹² is aryl or heteroaryl by standard palladium or coppercoupling reactions using the appropriate aryl or heteroaryl halide. The4,5-dihydropyridazinone may be oxidized to an aromatic pyridazinoneusing MnO₂, CuCl₂, DDQ, selenium oxide, DMSO/base or sodium3-nitrobenzenesulfonate in the presence of sodium hydroxide.

In Scheme 1, examples of compounds disclosed herein may be obtained bycondensation of an intermediate keto acid for example,4-(4-methoxyphenyl)-4-oxobutyric acid (or an ester derivative) withhydrazine or an n-substituted hydrazine derivative in a solvent such asethanol or 2-propanol to produce a dihydropyridazinone intermediate. Theketo-acid intermediates not commercially available are readily preparedand described using literature methods. Keto-acid intermediates with R¹³or R¹⁴ groups in the 4 or 5-positions or fused aryl or heteroaryl groupsare described (Heterocycles, 2002, 57, 39; Indian J. Chem, 1977, 16B,631; Chem Pharm Bull, 1980, 42, 1850; J. Med. Chem. 2003, 46, 2008). TheN2 position may be substituted with alkyl or substituted alkyl groupsusing a base, for example K₂CO₃, Cs₂CO₃ or NaH in an inert solvent suchas DMF or CH₃CN. In cases where R¹³ or R¹⁴ substituteddihydropyridazinone form isomers, the individual isomers may beseparated using conventional methods known to the art. R¹³ aryl orheteroaryl groups may be introduced by standard palladium or coppercoupling reactions using the appropriate aryl or heteroaryl halide.Alternatively, the 4,5-position may be oxidized to the pyridazinoneintermediate using for example MnO₂, CuCl₂, DDQ or selenium oxide as theoxidizing agent. The N2 nitrogen may be H, or further substituted usingmethods outlined previously.

As outlined in Scheme 1 and 2, the pyridazinone or dihydro pyridazinonemethoxy intermediate is demethylated using BBr₃ in dichloromethane toproduce the phenol. Alkylation of the phenol with bromochloropropane ora dibromoalkane intermediate in a suitable solvent such as DMF, acetone,butanone or CH₃CN with K₂CO₃ produces the halogen intermediate.Alkylation of the halide intermediate with an amine gives the targetdihydropyridazinone examples of the invention. Other suitable leavinggroups may be used such as mesylates as precursors to amines. Mitsunoboreactions with cyclic amino-ethers such as 4-hydroxypiperidine,3-hydroxypyrrolidine or substituted amino alcohols produce thecorresponding examples. Alkyl bridged analogs or linker group withhetero atoms can readily be prepared for example from methoxy indanones,tetralones, benzocycloheptanones, dihydro-2H-benzo[b]oxepinones,dihydro-2H-benzo[b]thiepinones, chromanones, or thiochromanones.

As outlined in Schemes 3 and 4, the pyridazinone or4,5-dihydropyridazinone was demethylated using BBr₃ in dichloromethaneto produce phenol intermediates III and IIIa. Alkylation of the phenolintermediates with 3-bromo-1-chloropropane or a dibromo intermediate ina suitable solvent such as DMF, acetone, butanone or CH₃CN with K₂CO₃produced the corresponding alkylated intermediate. Displacement of thehalide with an amine gave the target dihydropyridazinone examples ofgeneral structures V and Va.

As outlined in Scheme 5, the phenol intermediate was coupled underMitsunobo conditions with hydroxypiperidines, pyrrolidines or azepinesto give the piperidine or cyclic amine derivatives of general structureVI. Using reaction conditions described previously, examples of generalstructure VII was prepared.

Scheme 6 discloses an Aldol condensation route to examples wherein R¹²is H. 4-Hydroxy-acetophenone or a derivative thereof was condensed witha keto-acid, for example glycolic acid in acetic acid, and cyclized withhydrazine to give an aromatic pyridazinone (J. Med. Chem., 1987, 30,239).

5-Aryl pyridazinone examples were synthesized as outlined in Schemes 7and 8. Condensation of 4-methoxyphenyl acetone (R¹⁴=Me) with glyoxylicacid (Scheme 7), followed by cyclization with hydrazine hydrate orN-substituted hydrazine derivatives afforded5-(4-methoxy-phenyl)-6-methyl-2H-pyridazin-3-one, and N—R¹² examples(Farmaco, 1987, 43, 539).

5-Aryl examples where R¹⁴ is H were prepared as outlined in Scheme 8starting from 4-methoxyphenylacetaldehyde using conditions shown inScheme 7.

Aza examples (X═N) where R¹³ and R^(13a) are each methyl were preparedas outlined in Scheme 9 by alkylation of1-(6-chloropyridin-3-yl)ethanone with 4-hydroxy-N-Boc-piperidine and abase such as NaH, potassium tertiary butoxide, or KHMDS in DMSO, DMF orTHF. A second alkylation step using potassium bis(trimethylsilyl)amidein toluene and, for example 2-bromo-2-methyl-propionic acid ethyl ester,produced the keto-ester intermediates VIII. Example 148 was produced asshown in Scheme 9 using conditions described previously.

Scheme 10 shows the route to aza (X═N) examples where R¹² isheteroaryl(For example, Example 149(6-[6-(1-Cyclobutyl-piperidin-4-yloxy)-pyridin-3-yl]-2-pyridin-2-yl-2H-pyridazin-3-one).6-(6-Chloropyridin-3-yl)-4,5-dihydro-2H-pyridazin-3-one intermediate IX,prepared from ethyl-4-(4-chloro-3-pyridyl)-4-oxobutyrate and hydrazinein ethanol was alkylated with 4-hydroxy-boc-piperidine and a base(KHMDS, DMSO) to intermediate X and converted to example 141 usingmethods described previously. Treatment of Example 141 with2-bromopyridine in the presence of copper(I)iodide gives Example 149.Using aryl halides or heteroaryl halides gave examples where R¹² is arylor heteroaryl.

Bridged examples (Scheme 11) were prepared using methoxy tetralones andglycolic acid in an aldol synthesis. Phenol formation and alkylations asdescribed previously produced the N-substituted examples. Alternatively,the use of β-tetralones provided a route to pyridazinone regioisomers.

Scheme 12 shows bridged analogs where R¹² is H, prepared by varying theorder of the reactions. Addition of Zn dust to the aldol/ring closureprocedure gave a one-pot synthesis of the dihydropyridazinone.

The present invention will now be illustrated by reference to thefollowing specific, non-limiting examples. Those skilled in the art oforganic synthesis may be aware of still other synthetic routes to theinvention compounds. The reagents and intermediates used herein arecommercially available or may be prepared according to standardliterature procedures.

EXAMPLES

Other features of the invention will become apparent in the course ofthe following descriptions of exemplary embodiments as shown below. Thecompounds shown herein have activity in the targets described herein atconcentrations ranging from 0.1 nM to 10 μM. These examples are givenfor illustration of the invention and are not intended to be limitingthereof.

Example 1

2-Methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-oneStep 1

6-(4-Methoxy-phenyl)-2-methyl-4,5-dihydro-2H-pyridazin-3-one

In a 500 mL round bottom flask, 4-(4-methoxyphenyl)-4-oxobutyric acid(27 g, 132 mmol) and methylhydrazine (7.3 g, 8.5 mL, 159 mmol) in2-propanol (150 mL) were stirred at reflux 12 h. The solvent wasconcentrated to about 50 mL, ether was added (˜50 mL) and the productcollected by filtration, washed 1× with ether and dried under housevacuum. Yield 27 g (94%, purity >95%), mp 133-135° C. ¹H NMR (CDCl₃) δ2.57 (m, 2H), 2.9 (m, 2H), 3.4 (s, 3H), 3.8 (s, 3H), 6.9 (d, 2H), 7.6(d, 2H). MS m/z=218 (M+H).

Step 2

6-(4-Methoxy-phenyl)-2-methyl-2H-pyridazin-3-one

Method A: In a 1 L round bottom flask,6-(4-methoxyphenyl)-2-methyl-4,5-dihydro-2H-pyridazin-3-one (27 g, 124mmol) and MnO₂ (30 g, 345 mmol) in xylene (250 mL) was stirred atvigorous reflux 14 h. The reaction was cooled to rt and filtered througha pad of celite. The xylene was concentrated and the resulting yellowsolid was triturated with ether/hexane (1:2) and collected to produce 20g (75%, HPLC 98% purity) of product. The celite/MnO₂ pad was washed withCHCl₃:MeOH 9:1 (2×˜100 mL), filtered and concentrated. The residue wastriturated with ether/hexane (1:2) and collected to give a second crop(4 g, 15%, 96% purity) total yield 24 g (90%). mp 109-110° C. ¹H NMR(DMSO-d₆) δ 3.75 (s, 3H), 3.85 (s, 3H), 7.0-7.05 (d, 2H, d, 1H), 7.82(d, 2H), 8.01 (d, 1H); MS m/z=216 (M+H).

Method B: A mixture of6-(4-methoxyphenyl)-2-methyl-4,5-dihydro-2H-pyridazin-3-one (3.27 g, 15mmol) and Cu(II)Cl₂ (3.96 g, 2 eq., anhydrous, Acros) in 45 ml ofanhydrous acetonitrile was refluxed for 2 hr. HPLC indicated thecompletion of the reaction (rt (product)=7.66 min, rt (SM)=7.88 min).The reaction was cooled to rt and poured into ice-water (˜100 ml) andthe acetonitrile removed at reduced pressure. The resulting off-whitesolid was filtered off, washed with water, and then crystallized fromEtOH:Et₂O to give the product (2.47 g, 76%).

Step 3

6-(4-Hydroxy-phenyl)-2-methyl-2H-pyridazin-3-one

To 6-(4-methoxyphenyl)-2-methyl-2H-pyridazin-3-one (10 g, 46.3 mmol) in15 mL DCM cooled on an ice-water bath to ˜5° C. was added 93 mL of BBr₃(1M soln in DCM) over 5 min. The ice bath was removed and the solutionstirred at rt for 4 h. The reaction was cooled on an ice-bath andsaturated NH₄Cl solution (100 mL) added slowly. After the addition wascomplete, the DCM was removed under reduced pressure, excess water addedand the product collected, washed 1× with MeOH (˜20 mL) and dried togive 9.2 g (98%): Mp 242-245° C. ¹H NMR (DMSO-d₆) δ 3.8 (s, 3H), 6.85(d, 2H), 7.0 (d, 1H), 7.7 (d, 2H), 7.95 (d, 1H), 9.8 (s, 1H); MS m/z=203(M+H).

Step 4

6-[4-(3-Chloro-propoxy)-phenyl]-2-methyl-2H-pyridazin-3-one

Phenol from step 3 (500 mg, 2.3 mmol), 3-bromo-1-chloropropane (720 mg,4.6 mmol) and K₂CO₃ (950 mg) in CH₃CN (25 mL) was stirred at reflux 20h. The reaction was filtered and concentrated. The resulting oil wasdissolved in Et₂O, and washed with water, NaCl solution, dried (MgSO₄)and concentrated. The product was triturated with Et₂O-hexanes to yield580 mg (91%) mp 186-187° C. ¹H NMR (DMSO-d₆) δ 2.2 (t, 2H), 3.7 (s, 3H),3.8 (t, 2H), 4.15 (t, 2H), 7.0-7.1 (m, 3H), 7.8 (d, 2H), 8.0 (d, 1H). MSm/z=279 (M+H).

Step 5. Example 1

2-Methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one

6-[4-(3-Chloropropoxy)phenyl]-2-methyl-2H-pyridazin-3-one (1.5 g, 5.4mmol), K₂CO₃ (2.2 g 16.2 mmol), NaI (805 mg, 5.4 mmol)R-methylpyrrolidine HCl (1.3 g, 10.8 mmol) in CH₃CN (30 mL) was heatedunder N₂ at 90° C. for 2 days. The reaction was filtered andconcentrated. The residue was dissolved in EtOAc and washed with 2NNa₂CO₃ (1×), NaCl solution (1×) dried (MgSO₄) and concentrated. Theproduct was purified by ISCO chromatography (80 g silica gel column,95:5 DCM:MeOH). The fractions were combined and concentrated to yield850 mg (48%) of free base. The HCl was prepared by adding a 1N HCl-ethersolution to the based in ether. The product was collected, andrecrystallized from CH₃CN-ether. mp 183-185° C. ¹H NMR (DMSO-d₆) δ 1.38(d, 3H), 1.62 (m, 1H), 1.92-1.3.1 (m, 3H), 3.4 (m, 3H), 3.7 (m, 1H), 3.7(s, 3H), 4.15 (m, 2H), 7.0-7.17 (m, 3H), 7.8 (d, 2H), 8.0 (d, 1H), 10.1(s, 1H). MS m/z=328 (M+H).

Example 11

6-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-oneStep 1

1-[4-(3-Chloro-propoxy)-phenyl]-ethanone

A mixture of 1-(4-hydroxyphenyl)ethanone (20.4 g, 150 mmol), K₂CO₃ (62.1g, 3.0 eq.), and 3-bromo-1-chloropropane (29.6 mL, 2.0 eq.) in CH₃COCH₃(200 mL) was heated to 65° C. overnight. The mixture was filtered,washed with acetone, and concentrated to dryness. The crude product wasdissolved in 150 mL of CH₂Cl₂, and washed with saturated NaHCO₃, NaClsolution and dried over Na₂SO₄. Concentration to dryness under vacuumafforded product (31.5 g, 99% yield): MS m/z 213 (M+H).

Step 2

6-[4-(3-Chloro-propoxy)-phenyl]-2H-pyridazin-3-one

A mixture of the product from step 11 (4.6 g, 1.0 eq.) and glyoxalicacid monohydrate (4.6 g, 1.0 eq.) was stirred in 15 mL of acetic acid at100° C. for 2 h. The solvent was evaporated and to the residue was added25 mL of water, and cooled to 0° C. while conc. aqueous NH₄OH was addedto pH 8. To this mixture, hydrazine hydrate (4.76 mL, 2 eq.) was addedand heated to 100° C. for 1 h. The resulting solid was filtered, washedwith water. The crude material was dissolved in CH₂Cl₂/MeOH and purifiedby column chromatography with CH₂Cl₂ to 10% MeOH in CH₂Cl₂; Mp 191-3°C.; MS m/z 265 (M+H).

Step 3

6-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one

A mixture of the product from step 2 (5.5 g, 21 mmol), K₂CO₃ (3.5 eq,10.1 g), 100 mg of NaI, and R-2-methylpyrrolidine hydrochloride (2 eq.,5.1 g) in 250 mL of acetonitrile was heated to 80° C. for 2 days. Thereaction mixture was then filtered, washed with CH₂Cl₂ (2×50 mL), andconcentrated. The residue was dissolved in 200 mL of CH₂Cl₂, and washedwith saturated NaHCO₃, saturated NaCl, dried with Na₂SO₄ andconcentrated. The residue was purified by ISCO graduate chromatographywith 100% CH₂Cl₂ to 5% MeOH:95% CH₂Cl₂:0.5 mL of 2-aminopropane and thento 10% MeOH:90% CH₂Cl₂:0.5 mL of 2-aminopropane to give the product. Theproduct was dissolved in 15 mL of MeOH and then added 30 mL of 0.5 N HClin EtOH. Evaporation of the solvent, and crystallization from MeOH:Et₂Oafforded the example 11 as the HCl salt (2.65 g, 41%): Mp 240-2° C.; MSm/z 314 (M+H).

The following examples were prepared as HCl salts unless noted usingmethods for example 1 and example 11. The 4,5-dihydro examples wereprepared using the method for step 3 on the product from step 1.

Example Structure Mp (° C.) MS m/z 2

200-201 328 (M + H)2-Methyl-6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one 3

118-122 356 (M + H)2-Isopropy1-6-[4-(3-piperidin-1-yl-propoxy)-pheny1]-2H-pyridazin-3-one 4

76-77 358 (M + H)2-Isopropy1-6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one 5

60-64 (tartrate) 356 (M + H)2-Isopropyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 6

58-62 (tartrate) 342 (M + H) 2-Ethyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 7

140-142 346 (M + H) 6-{3-Fluoro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-methyl-2H-pyridazin-3-one 8

140-146 375 (M + H)2-(2,4-Dichloro-benzyl)-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one 9

214-222 450 (M + H) 2-(3,5-Dichloro-phenyl)-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 10

230-232 408 (M + H) 6-[3-Fluoro-4-(3-piperidin-1-yl-propoxy)-phenyl]-2-phenyl-2H-pyridazin-3-one 81

190-191 408 (M + H) 6-{3-Fluoro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-phenyl-2H-pyridazin-3-one 11

240-2  314 (M + H) 6-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 12

147 354 (M + H) 4-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2,5,6,7-tetrahydro-cyclopenta[d]pyridazin-1-one 13

188-190 342 (M + H) 2-Methyl-6-{4-[(S)-2-methyl-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 82

76-78 342 (M + H) 2-Methyl-6-{4-[(R)-2-methyl-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 14

169 344 (M + H) 6-{4-[3-((S)-2-Hydroxymethyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-methyl-2H-pyridazin-3-one 15

166-7  344 (M + H) 6-{4-[3-((R)-2-Hydroxymethyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-methyl-2H-pyridazin-3-one 16

145-147 330 (M + H) 2-Methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one 17

56-58 406 (M + H) 2-Benzyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one 18

228-230 404 (M + H) 2-Benzyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 19

213-215 392 (M + H) 6-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-phenyl-2H-pyridazin-3-one 20

82-86 390 (M + H) 6-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-phenyl-2H-pyridazin-3-one 84

175-178 base 364 (M + H) 6-{3,5-Difluoro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-methyl-2H-pyridazin-3-one 85

178 dec. 362 (M + H) 6-{3-Chloro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-methyl-2H-pyridazin-3-one

Example 21

2-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one

A mixture of R-1-[3-(4-bromo-phenoxy)-propyl]-2-methyl-pyrrolidine (560mg, 1.87 mmol), 2H-pyridazin-3-one (180 mg, 1.87 mmol), K₂CO₃ (775 mg,5.61 mmol), copper powder (120 mg, 1.87 mmol) in pyridine (75 mL) wasstirred at reflux under nitrogen for 18 h. The reaction was cooled to rtand concentrated at reduced pressure. The residue was dissolved ontofluorsil for elution and purification by ISCO silica gel chromatography(95:5:1/DCM, MeOH, isopropyl amine). The fractions containing pureproduct were collected and concentrated. The solid was recrystallizedfrom Et₂O-hexanes to give 210 mg of Example 21 as a white solid; Mp106-107° C. The HCl salt was prepared by dissolving the base in MeOH andadding 1N Et₂O—HCl: Mp 175-177° C. (MeOH-Et₂O); MS m/z 314 (M+H).

Example 22

5-Isopropyl-7-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5H-thieno[2,3-d]pyridazin-4-oneStep 1

7-(4-Methoxy-phenyl)-5H-thieno[2,3-d]pyridazin-4-one

A solution of 3-thiophenecarboxylic acid (10 g, 78 mmol) in 250 mL ofTHF at 0° C. under N₂ was added 2.0 M LDA (2.2 eq., 86 mL) dropwise.After 10 min at 0° C., p-anisaldehyde (10.6 mL, 1.12 eq.) was added andthe mixture was slowly warmed to room temperature overnight. Thereaction was stirred for ˜14 h, after which 100 mL of ice-water wasadded, and the solvent was evaporated. The aqueous solution was washedwith EtOAc (2×40 mL), and then added KMnO₄ (2 eq., 12.4 g) dropwise at0° C. The ice-bath was removed and the reaction was heated to 60° C. for3 h. The solid was collected and washed with hot water. The aqueouslayer was acidified to pH ˜3, extracted with EtOAc (3×50 mL). Thecombined EtOAc was dried and evaporated. The crude solid was dissolvedin 50 mL of EtOH, and NH₂NH₂.H₂O (1.5 eq., 1.5 mL) was added dropwise.The reaction was heated to 80° C. for 3 h, and the resulting solid wascollected and washed with EtOH to give 3.6 g (36%): MS m/z 259 (M+H).

Step 2

5-Isopropyl-7-(4-methoxy-phenyl)-5H-thieno[2,3-d]pyridazin-4-one

A solution of the product from step 1 in 10 mL of DMF was added Cs₂CO₃(2 eq. 1.95 g) and 2-iodopropane (1.2 eq., 360 uL). The reaction washeated to 80° C. for 2 h, and then filtered through celite, washed withMeOH:CH₂Cl₂ (95:5). The filtrate was concentrated and purified by silicagel flash chromatography (MeOH:CH₂Cl₂, 97:3) to afford 585 mg (65%) ofthe product: Mp 124-6° C.; MS m/z 301 (M+H).

Step 3

7-(4-Hydroxy-phenyl)-5-isopropyl-5H-thieno[2,3-d]pyridazin-4-one

A solution of the product from step 2 (1.0 g, 3.3 mmol) in 25 mL ofCH₂Cl₂ was cooled to 0° C. and BBr₃ (1M in DCM, 16.7 mL) was addeddropwise. The ice-bath was removed and the reaction was stirred at rtfor 1 h. The reaction mixture was then poured into 50 mL of ice coldsaturated NH₄Cl solution with stirring. The resulting solid wascollected, washed with water (3×15 mL), and Et₂O (2×15 mL) to give theproduct of step 3 (868 mg, 92%): Mp 256-257° C.; MS m/z 287 (M+H).

Step 4

7-[4-(3-Chloro-propoxy)-phenyl]-5-isopropyl-5H-thieno[2,3-d]pyridazin-4-one

A solution of the product of step 3 (858 mg, 3 mmol), K₂CO₃ (1.24 g, 3.0eq.), and 3-bromo-1-chloropropane (0.3 mL, 1.05 eq.) in acetone:DMF (25mL:3 mL) was heated to 80° C. overnight. The mixture was then filtered,washed with acetone, and concentrated to dryness to afford the productof step 4 (1.17 mg, 98% yield): Mp 92-4° C.; MS m/z 363 (M+H).

Step 5

5-Isopropyl-7-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5H-thieno[2,3-d]pyridazin-4-one

A mixture of the product of step 4 (109 mg, 0.3 mmol), K₂CO₃ (3.5 eq,145 mg), 50 mg of NaI, and R-2-methylpyrrolidine hydrochloride (1.2 eq.,44 mg) in 10 mL of acetonitrile was heated to 80° C. for 2 days. Thereaction mixture was then filtered, washed with CH₂Cl₂ (2×20 mL) andconcentrated. The residue was dissolved in 20 mL of CH₂Cl₂, and washedwith saturated NaHCO₃ solution, saturated NaCl solution, dried withNa₂SO₄, and concentrated. The residue was purified by preparative TLC orISCO graduate silica gel chromatography (MeOH:CH₂Cl₂:2-aminopropane;5:95:0.5) to give the product. The product was dissolved in 5 mL ofMeOH, and added 0.5 mL of 1N HCl in EtOH. Evaporation of the solvent,and crystallization from MeOH:Et₂O afforded the HCl salt of example 22(5-isopropyl-7-(4-(3-((R)-2-methyl-pyrrolidin-1yl)propoxy)phenyl)-5H-thieno[2,3-d]pyridazin-4-one)(52 mg, 42%): Mp 123-4° C.; MS m/z 412 (M+H).

The following examples were prepared as HCl salts using methods ofexample 22.

Example Structure Mp (° C.) MS m/z 23

158-159 426 (M + H) 7-{4-[3-(2,5-Dimethyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5-isopropyl-5H-thieno[2,3-d]pyridazin-4-one 24

195-196 412 (M + H) 5-Isopropyl-7-[4-(3-piperidin-1-yl-propoxy)-phenyl]-5H-thieno[2,3-d]pyridazin-4-one 25

100-102 440 (M + H) 7-{4-[3-(3,3-Dimethyl-piperidin-1-yl)-propoxy]-phenyl}-5-isopropyl-5H-thieno[2,3-d]pyridazin-4-one 26

83 dec. 442 (M + H) 5-Isopropyl-7-{4-[3-((S)-2-methoxymethyl-pyrrolidin-1-yl)propoxy]-phenyl}-5H-thieno[2,3-d]pyridazin-4-one 27

 9-96 442 (M + H) 5-Isopropyl-7-{4-[3-((R)-2-methoxymethyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5H-thieno[2,3-d]pyridazin-4-one 28

188-190 400 (M + H) 7-[4-(3-Diethylamino-propoxy)-phenyl]-5-isopropyl-5H-thieno[2,3-d]pyridazin-4-one 29

144 398 (M + H) 5-Isopropyl-7-[4-(3-pyrrolidin-1-yl-propoxy)-phenyl]-5H-thieno[2,3-d]-pyridazin-4-one 30

283 dec. 481 (M + H) 5-Isopropyl-7-{4-[3-(4-pyrrolidin-1-yl-piperidin-1-yl)-propoxy]-phenyl}-5H-thieno[2,3-d]pyridazin-4-one 31

106 dec. 426 (M + H) 7-{4-[3-((2R,5R)-2,5-Dimethyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5-isopropyl-5H-thieno[2,3-d]pyridazin-4-one 32

151-153 412 (M + H) 7-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]phenyl}-5-propyl-5H-thieno[2,3-d]pyridazin-4-one 33

84 dec. 426 (M + H) 7-{4-[3-((2R,5R)-2,5-Dimethyl-pyrrolidin-1-yl)-propoxy]-phenyl)-5-propyl-5H-thieno[2,3-d]pyridazin-4-one 34

168-170 426 (M + H) 7-{4-[3-(4-Methyl-piperidin-1-yl)-propoxy]-phenyl}-5-propyl-5H-thieno[2,3-d]pyridazin-4-one 35

207-209 455 (M + H) 7-{4-[3-(4-Dimethylamino-piperidin-1-yl)-propoxy]-phenyl}-5-propyl-5H-thieno[2,3-d]pyridazin-4-one 36

123 dec. 481 (M + H)5-Propyl-7-{4-[3-((S)-2-pyrrolidin-1-ylmethyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5H-thieno[2,3-d]pyridazin-4-one 37

227-229 494 (M + H) 5-(4-Chloro-benzyl)-7-[4-(3-piperidin-1-yl-propoxy)-phenyl]-5H-thieno[2,3-d]pyridazin-4-one 38

223-224 494 (M + H)5-(4-Chloro-benzyl)-7-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5H-thieno[2,3-d]pyridazin-4-one

Example 39

2,4-Dimethyl-6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one

Step 1. A solution of 2-methoxy-4-oxo-4-(4′-methoxyphenyl)butyric acid(2.22 g, 10 mmol) and hydrazine hydrate (1.5 eq., 688 μL) in 20 mL ofEtOH was stirred at 80° C. overnight. The solvent was removed and thesolid was collected and washed with cold EtOH to give6-(4-methoxy-phenyl)-4-methyl-4,5-dihydro-2H-pyridazin-3-one (2.05 g,94%): Mp 203-6° C.

Step 2. A mixture of the product from step 1(6-(4-methoxy-phenyl)-4-methyl-4,5-dihydro-2H-pyridazin-3-one; 1.96 g, 9mmol) and Cu(II)Cl₂ (2.48 g, 2 eq.) in of acetonitrile (15 mL) washeated to 70° C. for 2 h. The reaction was quenched with ice-water (˜100mL), the resulting solid was collected and crystallized from isopropanolto give 1.42 g (73%) of6-(4-methoxy-phenyl)-4-methyl-2H-pyridazin-3-one: Mp 265-7° C.; MS m/z217 (M+H).

6-(4-Methoxy-phenyl)-2,4-dimethyl-2H-pyridazin-3-one

Step 3. The product of step 2(6-(4-methoxy-phenyl)-2,4-dimethyl-2H-pyridazin-3-one) was prepared asdescribed for example 22 step 2 using6-(4-methoxy-phenyl)-4-methyl-4,5-dihydro-2H-pyridazin-3-one, MeI andCs₂CO₃.

Example 39

6-(4-(3-Chloropropoxy)-phenyl)-2,4-dimethyl-2H-pyridazin-3-one wasprepared from the product of step 3 and 3-bromo-1-chloropropane usingthe procedure described for Example 22 step 4. Example 39(2,4-dimethyl-6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one)was prepared using6-(4-(3-chloropropoxy)-phenyl)-2,4-dimethyl-2H-pyridazin-3-one andpiperidine by the methods described for example 22 step 5. Thehydrochloride salt was prepared; Mp 222-3° C.; MS m/z 342 (M+H).

The following examples as HCl salts were prepared using methodsdescribed for example 1 and example 22.

Example Structure Mp (° C.) MS m/z 40

175-176 342 (M + H) 2,4-Dimethyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 41

 54-155 370 (M + H) 2-Isopropyl-4-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 42

197-198 370 (M + H) 2-Isopropyl-4-methyl-6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one 43

190-192 418 (M + H) 2-Benzyl-4-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 44

232-233 418 (M + H) 2-Benzyl-4-methyl-6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one 45

232-233 418 (M + H) 4-Benzyl-2-methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 46

186-187 418 (M + H) 4-Benzyl-2-methyl-6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one 47

207-209 404 (M + H) 2-Methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5-phenyl-2H-pyridazin-3-one 48

212-214 404 (M + H) 2-Methyl-5-phenyl-6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one 49

216-217 378 (M + H) 2-Methyl-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-phthalazin-1-one 50

241-242 378 (M + H) 2-Methyl-4-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-phthalazin-1-one 51

253-254 364 (M + H) 2-Methyl-4-[4-(2-piperidin-1-yl-ethoxy)-phenyl]-2H-phthalazin-1-one 52

201-203 364 (M + H) 2-Methyl-4-[4-(3-pyrrolidin-1-yl-propoxy)-phenyl]-2H-phthalazin-1-one 53

238-240 392 (M + H) 4-[4-(3-Azepan-1-yl-propoxy)-phenyl]-2-methyl-2H-phthalazin-1-one 54

217-218 489 (M + H) 2-(4-Chloro-benzyl)-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-phthalazin-1-one 55

216-217 489 (M + H) 2-(4-Chloro-benzyl)-4-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-phthalazin-1-one 56

212-214 368 (M + H)2-Methyl-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2,5,6,7-tetrahydro-cyclopenta[d]pyridazin-1-one 57

214-216 368 (M + H) 2-Methyl-4-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2,5,6,7-tetrahydro-cyclopenta[d]pyridazin-1-one 58

<50 370 (M + H)2-Methyl-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2,4a,5,6,7,7a-hexahydro-cyclopenta[d]pyridazin-1-one 59

<50 370 (M + H) 2-Methyl-4-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2,4a,5,6,7,7a-hexahydro-cyclopenta[d]pyridazin-1-one 60

156-158 382 (M + H) 2-Methyl-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5,6,7,8-tetrahydro-2H-phthalazin-1-one 61

196-198 382 (M + H) 4-{4-[3-(Butyl-ethyl-amino)-propoxy]-phenyl}-2-methyl-5,6,7,8-tetrahydro-2H-phthalazin-1-one

4-Benzyl-6-(4-methoxy-phenyl)-2H-pyridazin-3-one

6-(4-methoxy-phenyl)-4,5-dihydro-2H-pyridazin-3-one (1.65 g, 7.5 mmol)in 15 mL of EtOH was heated to 80° C. as 20 mL of 4% of KOH/EtOHsolution was added dropwise. After 5 min., benzaldehyde (1.0 eq. 0.76mL) was added and the mixture stirred at 80° C. for 2 h. The reactionwas cooled to rt., poured into ice-H₂O (75 mL) and the resulting solidwas collected and crystallized from EtOH to give 1.67 g (76%) ofintermediate 4-benzyl-6-(4-methoxy-phenyl)-2H-pyridazin-3-one: MS m/z293 (M+H). This intermediate was used to prepare examples 45 and example46.

6-(4-Methoxy-phenyl)-2-methyl-5-phenyl-2H-pyridazin-3-one

Step 1. A suspension of NaH (12.8 mmol, 512 mg) in DMSO (23 mL) wasadded 4′-methoxy-2-phenylacetophenone (12.8 mmol, 2.89 g) in 10 mltoluene dropwise under argon. After 30 minutes of stirring, ethylbromoacetate (1.4 mL, 1 eq.) in 10 mL of toluene was added and themixture was stirred at rt overnight. The reaction was quenched byaddition of 2N HCl (4 mL), and then 60 mL of water. The mixture wasextracted with CH₂Cl₂ (3×30 mL), dried over MgSO₄ and concentrated undervacuum overnight to afforded 4.0 g (99%) of4-(4-methoxy-phenyl)-4-oxo-3-phenyl-butyric acid ethyl ester.

Step 2. A solution of 4-(4-methoxy-phenyl)-4-oxo-3-phenyl-butyric acidethyl ester (5.0 g, 16 mmol) in EtOH:H₂O (60 mL 1:1) was stirred as 10NNaOH (16 mL) was added dropwise. The reaction was stirred at rt for 1hr. The solvent was evaporated and the residue was diluted with water(50 mL) and extracted with CH₂Cl₂ (2×20 mL). The aqueous layer was thenacidified with 3N HCl to pH ˜2-3, extracted with CH₂Cl₂ (3×30 mL). TheCH₂Cl₂ extracts were dried over MgSO₄, and the oil was crystallized fromEt₂O/MeOH to give 4.5 g (99%) of4-(4-methoxy-phenyl)-4-oxo-3-phenyl-butyric acid: mp 157-9° C.; MS m/z283 (M−H).

Step 3. A solution of 4-(4-methoxy-phenyl)-4-oxo-3-phenyl-butyric acid(1.5 g, 5.28 mmol) and hydrazine hydrate (1.5 eq., 363 μL) in 20 mL ofEtOH was stirred at 80° C. overnight. The solvent was reduced and thesolid was filtered and then washed with cold EtOH to give6-(4-methoxy-phenyl)-5-phenyl-4,5-dihydro-2H-pyridazin-3-one (1.46 g,99%): mp 176-7° C.; MS m/z 281 (M+H).

Examples 47 and 48 were prepared from6-(4-methoxy-phenyl)-5-phenyl-4,5-dihydro-2H-pyridazin-3-one asdescribed in Example 39.

Example 62

4-[4-(3-Methyl-4-oxo-3,4-dihydro-phthalazin-1-yl)-phenoxymethyl]-piperidine-1-carboxylicacid tert-butyl ester

A suspension of 4-(4-hydroxy-phenyl)-2-methyl-2H-phthalazin-1-one (252mg, 1.0 mmol) and of 4-bromomethyl)piperidine-1-carboxylic acid t-butylester (786 mg, 3 eq) in 1 mL of 4N NaOH and 8 mL of DMSO was stirred atrt for 24 h. The reaction was diluted with water (20 mL), extracted withEtOAc (3×10 mL), and the combined extracts were washed with NaHCO₃solution, NaCl solution and dried over MgSO₄. The product was purifiedby ISCO graduate chromatography (100% CH₂Cl₂ to 95:5 CH₂Cl₂:MeOH) toafford 198 mg (50%) of4-(4-(1(3-methyl-4-oxo-3,4-dihydro-phthalazin-1-yl)-phenoxymethyl)-piperidine-1-carboxylicacid t-butyl ester: Mp 167-9° C.; MS m/z 450 (M+H).

Example 63

2-Methyl-4-[4-(piperidin-4-ylmethoxy)-phenyl]-2H-phthalazin-1-one

A solution of example 62(4-(4-(1(3,-methyl-4-oxo-3,4-dihydro-phthalazin-1-yl)-phenoxymethyl)-piperidine-1-carboxylicacid tert-butyl ester) (180 mg, 0.4 mmol) and 4N HCl (2 mL) in dioxane(5 mL) and water (0.5 mL) was heated to 50° C. for 2 h. The solvent wasevaporated, and the product was triturated with Et₂O to give 117 mg(84%) of example 63(2-methyl-4-(4-(piperidin-4-ylmethoxy)-phenyl)-2H-phthalazin-1-one) HCl:Mp 207-9° C.; MS m/z 350 (M+H).

Example 64

4-[4-(1-Cyclobutyl-piperidin-4-ylmethoxy)-phenyl]-2-methyl-2H-phthalazin-1-one

A solution of example 63(2-methyl-4-(4-(piperidin-4-ylmethoxy)-phenyl)-2H-phthalazin-1-one) (90mg, 0.23 mg) and NaCNBH₃ in DMF:MeOH:AcOH (3:6 mL:0.25 mL) was stirredunder N₂ as cyclobutanone (81.7 mg, 5 eq.) was added. The reaction wasstirred at 60° C. for 1.5 h, quenched with 3 mL of water, extracted withCH₂Cl₂ (3×10 mL), washed with NaHCO₃, NaCl solution, dried andconcentrated. The crude product was purified by silica gelchromatography using 5% MeOH:95% CH₂Cl₂:0.5 mL of isopropyl amine. Thefractions were collected, concentrated and the product dissolved in 5 mLof MeOH, and added 0.5 mL of 1N HCl in EtOH. The solvent was evaporated,and the HCl product crystallized from MeOH-Et₂O to give example 64(4-(4-(1-cyclobutyl-piperidin-4-ylmethoxy)-phenyl)-2-methyl-2H-phthalazin-1-oneHCl) (53 mg, 57%): Mp 256-7° C.; MS m/z 404 (M+H).

The following examples as HCl salts were prepared from6-(4-hydroxy-phenyl)-2-methyl-2H-pyridazin-3-one using the proceduresfor examples 62-64. Example 65 is the base.

Example Structure Mp (° C.) MS m/z 65

164-166 400 (M + H) 4-[4-(1-Methyl-6-oxo-1,6-dihydro-pyridazin-3-yl)-phenoxymethyl]-piperidine-1-carboxylic acid tert-butyl ester 66

249-251 300 (M + H) 2-Methyl-6-[4-(piperidin-4-ylmethoxy)-phenyl]-2H-pyridazin-3-one 67

250-252 354 (M + H) 6-[4-(1-Cyclobutyl-piperidin-4-ylmethoxy)-phenyl]-2-methyl-2H-pyridazin-3-one 68

187-189 342 (M + H) 6-[4-(1-Isopropyl-piperidin-4-ylmethoxy)-phenyl]-2-methyl-2H-pyridazin-3-one 69

230-231 354 (M + H) 6-[4-(1-Cyclopropylmethyl-piperidin-4-ylmethoxy)-phenyl]-2-methyl-2H-pyridazin-3-one 70

250-251 368 (M + H) 6-[4-(1-Cyclopentyl-piperidin-4-ylmethoxy)-phenyl]-2-methyl-2H-pyridazin-3-one 71

257-258 314 (M + H) 2-Methyl-6-[4-(1-methyl-piperidin-4-ylmethoxy)-phenyl]-2H-pyridazin-3-one

Example 72

A mixture of 6-(4-hydroxy-phenyl)-2-methyl-2H-pyridazin-3-one (500 mg,2.6 mmol), triphenylphosphine (1.35 g, 5.2 mmol),4-hydroxy-N-iPr-piperidine (745 mg, 10.4 mmol) in THF (50 mL) was addedDEAD (1.1 g, 6.5 mmol) dropwise. The reaction was stirred at rtovernight, then concentrated. The product was purified by ISCO silicagel chromatography (95:5. DCM:MeOH). The HCl salt was prepared byaddition of 1M Et₂O HCl to a methanol solution of the base. mp 108-110°C. MS m/z 328 (M+H).

Example 73

A solution of 6-(4-hydroxy-phenyl)-2-methyl-2H-pyridazin-3-one (1.0 mg,4.6 mmol), triphenylphosphine (1.44 g, 5.5 mmol),4-hydroxy-N—BOC-piperidine (1.1 mg, 5.5 mmol), in THF (40 mL) was addedDEAD (0.96 g, 5.5 mmol) dropwise on an ice-batch. The batch was removedand the reaction was stirred at rt 2-days. The reaction was concentratedat reduced pressure and Et₂O (40 mL) was added and stirred 2 h and thesolids removed by filtration. The solution was concentrate and theproduct was purified by ISCO silica gel chromatography (95:5. DCM:MeOH).The resulting4-[4-(1-methyl-6-oxo-1,6-dihydro-pyridazin-3-yl)-phenoxy]-piperidine-1-carboxylicacid t-butyl ester was dissolved in dioxane (5 mL) and 4N HCl in dioxane(4 mL) as added and stirred 2 h. The solution was concentrated and 2NNa₂CO₃ added to pH 9. The aqueous solution was added solid sodiumchloride until saturated, then extracted with EtOAc (2×50 mL), dried(MgSO₄) and concentrated. The HCl salt was prepared by addition of 1MHCl Et₂O solution to a methanol solution of the base. Mp>210° C. MS m/z386 (M+H).

Example 74

To a solution of example 73 (0.25 g, 0.9 mmol) and cyclobutanone in MeOH(10 mL) was added HOAc (0.5 mL) then solid sodium cyanoborohydride (560mg, 62.8 mmol). The reaction was stirred 4 h then concentrated. Na₂CO₃solution was added, and extracted with EtOAc (2×50 mL), dried overMgSO₄, filtered and concentrated. To the residue in CH₃CN (3 mL) wasadded a 1N HCl/Et₂O solution and concentrated. Example 74 wasrecrystallized from CH₃CN-Et₂O to give 180 mg of a white solid. Mp250-252° C. MS m/z 340 (M+H).

Example 75 Step 1

A mixture of 6-methoxy-1-tetralone (20 g, 114 mmol) and glyoxylic acidmonohydrate (10.5 g, 114 mmol) was heated at 120° C. in a melt for 5min. After slight cooling, EtOAc (100 mL) was carefully added. The solidwhich precipitated was collected to afford 8.5 g (30%) ofhydroxyl-(6-methoxy-1-oxo-1,2,3,4-tetrahydro-naphthalen-2-yl)-aceticacid; Mp 212-214° C., MS m/z 251 (M+H).

Step 2

A solution of the product from step 1 (700 mg, 2.8 mmol) andN-methylhydrazine (0.3 mL) in 2-propanol (10 mL) was heated to reflux 18h. The solvent was removed under vacuum and the solid was trituratedwith methanol (2 mL), collected and then suspended in methylene chloride(2 mL) at 0° C. BBr₃ (10 mL of 1M solution in DCM, 10 mmol) was slowlyadded dropwise and the ice bath removed. After 3 h at ambienttemperature, saturated NH₄Cl solution (10 mL) was added. The DCM wasremoved under vacuum and the resulting slurry was carefully neutralizedwith saturated NaHCO₃ solution and washed with water. The solids werecollected to afford8-hydroxy-2-methyl-5,6-dihydro-2H-benzo[h]cinnolin-3-one (175 mg, 27%)as a white solid; mp>300° C. MS m/z 229 (M+H).

Step 3

2-Methyl-8-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-5,6-dihydro-2H-benzo[h]cinnolin-3-one

To a slurry of the product from step 2 (166 mg, 0.7 mmol)1-bromo-3-chloro-propane (126 mg, 0.9 mmol) and K₂CO₃ (110 mg, 0.8 mmol)in acetonitrile (5 mL) was stirred 18 h at 100° C. The solvent wasremoved under vacuum and the solids were partitioned between EtOAc (10mL) and water (10 mL). The organics were washed with EtOAc (2×10 mL),dried over MgSO₄ and the solvent was removed under vacuum. Silica gelchromatography with EtOAc/hexanes as eluent afforded 196 mg of theintermediate 3-chloropropylether (88%) as a white solid. The chlorointermediate was slurred (196 mg, 0.6 mmol) in acetonitrile (4 mL) andadded R-2-methyl-pyrrolidine tartrate (227 mg, 0.9 mmol), KI (20 mg, 0.1mmol) and K₂CO₃ (355 mg, 2.4 mmol). The reaction was stirred 18 h at100° C., and the solvent was removed under vacuum. The solids werepartitioned between CH₂Cl₂ (10 mL) and water (10 mL). The water layerwas washed with CH₂Cl₂ (3×10 mL). The combined organic layers were driedover Na₂SO₄ and concentrated under vacuum. Silica gel chromatographyusing CH₂Cl₂/MeOH (95:5) as eluent gave the product as an oil. The HClsalt was prepared from EtOH and 1M HCl in Et₂O to give 130 mg (52%) ofexample 75 as a white solid; Mp 192-194° C.; MS m/z 354 (M+H).

The following examples were prepared as HCl salts using the methodsdescribed for example 75.

Example Structure Mp (° C.) MS m/z 76

140-142 416 (M + H) 8-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-2-phenyl-5,6-dihydro-2H-benzo[h]cinnolin-3-one 77

206-208 438 (M + H) 2-Benzyl-8-(3-piperidin-1-yl-propoxy)-5,6-dihydro-2H-benzo[h]cinnolin-3-one 78

250-252 354 (M + H) 2-Isopropyl-8-(3-piperidin-1-yl-propoxy)-5,6-dihydro-2H-benzo[h]cinnolin-3-one

Example 79

2-Methyl-7-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-2H-phthalazin-1-one

Step 1. A solution of 2-formyl-5-methoxy-benzoic acid (1.0 g, 6.10 mmol)and methyl hydrazine (0.481 mL, 1.5 eq.) in ethanol (15 mL) was stirredat 85° C. for 1.5 days. The solvent was removed and the solid wascollected and washed with cold EtOH to give7-methyl-2-methyl-2H-phthalazin-1-one (780 mg): MS m/z 191 (M+H).

Step 2-3. 7-(3-Chloro-propoxy)-2-methyl-2H-phthalazin-1-one was preparedfrom 7-methyl-2-methyl-2H-phthalazin-1-one using the procedure describedin Example 22 Step 3, and Step 4.

The hydrochloride salt of example 79(2-methyl-7-(3-(R)-2-methyl-pyrrolidin-1-yl)-propoxy)-2H-phthalazin-1-one)was prepared using the procedure as described in Example 22 Step 5: Mp252-3° C.; MS m/z 302 (M+H).

The following examples were prepared as HCl salts using methods ofexample 79.

Ex- Structure Mp ample (° C.) MS m/z 79

252- 253 302 (M + H) 2-Methyl-7-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-2H-phthalazin-1-one 80

251- 252 302 (M + H) 2-Methyl-7-(3-piperidin-1-yl-propoxy)-2H-phthalazin-1-one

Example 83

6-[4-(1-Cyclopentyl-piperidin-4-yloxy)-phenyl]-2-methyl-2H-pyridazin-3-one

This compound was prepared using the same method as example 74 usingexample 73 and cyclopentanone in MeOH (10 mL)/HOAc (0.5 mL) followed bysolid sodium cyanoborohydride. The reaction was stirred 4 h thenconcentrated. Na₂CO₃ solution was added, and extracted with EtOAc (2×50mL), dried over MgSO₄, filtered and concentrated. Example 83 wasrecrystallized from CH₃CN-Et₂O to give a white solid. Mp 129-132° C. MSm/z 354 (M+H).

Example 86

2,6-Dimethyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-oneStep 1

5-(4-Methoxy-phenyl)-2,6-dimethyl-2H-pyridazin-3-one

A mixture of 1-(4-methoxyphenyl)propan-2-one (16.4 g, 100 mmol) andglyoxalic acid hydrate (9.20 g, 100 mmol) were heated to 135° C.overnight, then the water was distilled off at 120° C. for 2 h. Theresidue was taken up in 40 mL of ethanol with stirring asmethylhydrazine (10.5 mL, 200 mmol) was added dropwise. The reaction washeated to 85° C. overnight. The solvent was evaporated and the residuewas dissolved in 200 mL of methylene chloride and washed with 5% NaHCO₃solution (2×20 mL), saturated NaCl solution, then dried over Na₂SO₄ andconcentrated. The residue was purified by silica gel chromatography (2%MeOH in CH₂Cl₂) to give5-(4-methoxyphenyl)-2,6-dimethyl-2H-pyridazin-3-one (4.2 g) MS m/z 231(M+H).

Step 2

5-(4-Hydroxy-phenyl)-2,6-dimethyl-2H-pyridazin-3-one

A solution of the product from step 1 (3.2 g, 14 mmol) in CH₂Cl₂ (40 mL)was cooled to 0° C. and BBr₃ (6.6 mL, 5.0 eq.) was added dropwise. Theice-bath was removed and the reaction was stirred at rt for 1 h, afterwhich the reaction mixture was poured into 50 mL of ice cold saturatedNH₄Cl solution with stirring. The resulting solid was filtered, andwashed with water (3×15 mL) then Et₂O (2×15 mL) to give the product ofstep 2 (0.66 g, 22%): MS m/z 217 (M+H).

Step 3

5-[4-(3-Chloro-propoxy)-phenyl]-2,6-dimethyl-2H-pyridazin-3-one

A solution of the product from step 2 (710 mg, 3.29 mmol), K₂CO₃ (1.36g, 3.0 eq.) and 3-bromo-1-chloropropane (0.39 mL, 1.2 eq.) in CH₃COCH₃(30 mL) was heated to 80° C. overnight. The mixture was then filtered,washed with acetone and concentrated to dryness to afford the product ofstep 3 (950 mg, 98%): MS m/z 293 (M+H).

Step 4

2,6-Dimethyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one

A mixture of the product of step 3 (481 mg, 1.65 mmol), K₂CO₃ (3.5 eq,795 mg), 50 mg of NaI, and R-2-methylpyrrolidine hydrochloride (2.0 eq.,773 mg) in acetonitrile (10 mL) was heated to 80° C. for 2 days. Thereaction was then filtered, washed with CH₂Cl₂ (2×20 mL) andconcentrated. The residue was dissolved in 30 mL of CH₂Cl₂ and washedwith saturated NaHCO₃, saturated NaCl solution, dried with Na₂SO₄ andthen concentrated. The residue was purified by preparative TLC (10%MeOH:90% CH₂Cl₂:0.5 mL 2-aminopropane) to give the product. The productwas dissolved in 10 mL of MeOH, and was added 2.5 mL of 1N HCl in EtOH.The solvents were evaporated and the product crystallized from MeOH:Et₂Oto give example 86 as the HCl salt (231 mg, 41%): Mp 176-8° C.; MS m/z342 (M+H).

Example 87

2,6-Dimethyl-5-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one

This compounds was prepared using the procedure for example 86 using theproduct of step 3 and piperidine to give the hydrochloride salt; Mp210-211° C.; MS m/z 342 (M+H).

Example 88

6-Methyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-oneStep 1

1-[4-(3-Chloro-propoxy)-phenyl]-propan-2-one

A solution of 4-hydroxyphenylacetone (4.5 g, 30 mmol) and potassiumcarbonate (4.14 g, 3.0 eq.) in 50 mL of acetone was stirred under N₂ as1-bromo-3-chloro-propane was added dropwise. The reaction was heated to80° C. overnight. The mixture was then filtered through celite, washedwith acetone and concentrated to afford1-[4-(3-chloro-propoxy)phenyl]propan-2-one (6.3 g, 93% yield): MS m/z227 (M+H).

Step 2

5-[4-(3-Chloropropoxy)phenyl]-6-methyl-2H-pyridazin-3-one

5-[4-(3-Chloropropoxy)phenyl]-6-methyl-2H-pyridazin-3-one was preparedfrom the product from step 1 using the procedure described in Example 86step 1.

Step 3

6-Methyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one

6-Methyl-5-{4-[3-(®-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2(-1-pyridazin-3-one)hydrochloride salt was prepared from5-[4-(3-chloropropoxy)phenyl]-6-methyl-2H-pyridazin-3-one andR-2-methylpyrrolidine hydrochloride using the procedure described inExample 86 Step 4; Mp 115° C. (dec), MS m/z 329 (M+H).

Example 89

6-Methyl-5-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one

This compound was prepared using the procedure for example 88 using theproduct of step 2 and piperidine to give the hydrochloride salt Mp dec123 (dec.)° C.; MS m/z 328 (M+H).

Example 90

5-[4-(3-Azepan-1-yl-propoxy)-phenyl]-6-methyl-2H-pyridazin-3-one

This compound was prepared using the procedure for example 88 to givethe hydrochloride salt Mp 204-6° C.; MS m/z 342 (M+H).

Example 91

2-Methyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-oneStep 1

5-Hydroxy-4-(4-methoxy-phenyl)-5H-furan-2-one

A solution of 4-methoxyphenyl ethanol (15.0 g, 98.2 mmol) in 150 mL ofmethylene chloride was stirred at 0° C. while Dess-Martin periodinane(50 g, 1.2 eq.) was added in small portions. The ice-bath was removedand the reaction was stirred at rt for 1 h. The reaction mixture wasthen diluted with methylene chloride (100 mL), washed with 10% sodiumthiosulfate, saturated NaHCO₃ solution, water, saturated NaCl solution,and dried over Na₂SO₄. The product was purified using silica gelchromatography (100% hexanes to 20% EtOAC/hexanes) to afford 5.3 g (34%)of 4-methoxyphenyl acetaldehyde.

A suspension of glyoxalic acid hydrate (2.45 g, 26.6 mmol) andmorpholine hydrochloride (3.28 g, 26.35 mmol) in dioxane (25 mL) wasstirred as water (2 mL) was added. The homogeneous solution and4-methoxyphenyl acetaldehyde (3.8 g, 25.3 mmol) was then added and thesolution was stirred at reflux for 24 h. The solvent was evaporated anda solid was formed after addition of 20 mL of water. The solid wascollected and washed with water to give 5.1 g (98%) of the product: MSm/z 189 (M−17+H).

Step 2

5-(4-Methoxy-phenyl)-2-methyl-2H-pyridazin-3-one

A suspension of 5-hydroxy-4-(4-methoxyphenyl)-5H-furan-2-one (2.06 g, 10mmol) in 30 mL of ethanol was stirred as methylhydrazine (0.78 mL, 1.5eq) was added dropwise. The reaction was heated to reflux at 85° C. for2 h, then the solvent was reduced at reduced pressure to give a solid,which was collected and washed with cold EtOH to give 1.0 g (46%) of5-(4-methoxy-phenyl)-2-methyl-2H-pyridazin-3-one: MS m/z 217 (M+H).

Step 3

5-(4-Hydroxy-phenyl)-2-methyl-2H-pyridazin-3-one

5-(4-Hydroxyphenyl)-2-methyl-2H-pyridazin-3-one was prepared from5-(4-methoxy-phenyl)-2-methyl-2H-pyridazin-3-one with BBr₃ using theprocedure described in Example 86 Step 2; Mp 296-8° C.; MS m/z 203(M+H).

Step 4

5-[4-(3-Chloro-propoxy)-phenyl]-2-m ethyl-2H-pyridazin-3-one

5-[4-(3-Chloro-propoxy)-phenyl]-2-methyl-2H-pyridazin-3-one was preparedfrom 5-(4-hydroxy-phenyl)-2-methyl-2H-pyridazin-3-one with1-bromo-3-chloro-propane using the procedure described in Example 86Step 3; Mp 90-91° C.; MS m/z 279 (M+H).

Step 5

2-Methyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one

This compound was prepared as the hydrochloride salt from5-[4-(3-chloropropoxy)-phenyl]-2-methyl-2H-pyridazin-3-one andR-2-methylpyrrolidine using the procedure described in Example 86 Step4; Mp 222-3° C.; MS m/z 328 (M+H).

Example 92

2-Methyl-5-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one

This compound was prepared as the hydrochloride salt using5-[4-(3-chloropropoxy)-phenyl]-2-methyl-2H-pyridazin-3-one andpiperidine using the procedure described in Example 91 Step 5; Mp 253-4°C.; MS m/z 328 (M+H).

Example 93

5-[4-(3-Azepan-1-yl-propoxy)-phenyl]-2-methyl-2H-pyridazin-3-one

This compound was prepared as the hydrochloride salt using5-[4-(3-chloropropoxy)-phenyl]-2-methyl-2H-pyridazin-3-one and azepineusing the procedure described in Example 91 Step 5; Mp 247-8° C.; MS m/z342 (M+H).

Example 94

5-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyridin-2-yl-2H-pyridazin-3-oneStep 1

2-[4-(3-Chloro-propoxy)-phenyl]-ethanol

A mixture of 2-(4-hydroxyphenyl)ethanol (13.82 g, 100.0 mmol) andpotassium carbonate (34.0 g, 250.0 mmol) in 125.0 mL of acetone wasstirred as 1-bromo-3-chloropropane (24.0 g, 150.0 mmol) was addeddropwise. The reaction was stirred at 60° C. overnight, and thenfiltered through celite, washed with acetone and concentrated. Theresidue was dissolved in EtOAc (250 mL) and washed with 2N Na₂CO₃,water, and saturated NaCl solution. After drying over Na₂SO₄ thesolution was concentrated to give 21 g (98%): Mp 49-50° C.; MS m/z 197(M−H).

Step 2

[4-(3-Chloro-propoxy)-phenyl]-acetaldehyde

A solution of Dess-Martin periodinane (20.4 g, 48.0 mmol) in 200 mL ofmethylene chloride was stirred as 2-[4-(3-chloropropoxy)ethanol (8.59 g,40.0 mmol) in 60.0 mL of methylene chloride was added dropwise viaaddition funnel. The reaction was stirred at rt for 1 h, diluted withether (400 mL) and poured into 200 mL of 1.3 M NaOH solution. The etherlayer was separated and washed with 1.3 M NaOH solution (100 mL), wateruntil pH 7, and dried over Na₂SO₄. The product was purified using silicagel flash chromatography with 20% Et₂O in hexane to give 6.75 g (79.3%)of [4-(3-chloro-propoxy)phenyl]acetaldehyde: MS m/z 213 (M+H).

Step 3

4-[4-(3-Chloro-propoxy)-phenyl]-5-hydroxy-5H-furan-2-one

A suspension of glyoxalic acid hydrate (3.04 g, 33.1 mmol) andmorpholine hydrochloride (4.09 g, 33.1 mmol) in dioxane (48 mL) wasstirred as 4.5 mL of water was added. To the homogeneous solution[4-(3-chloropropoxy)phenyl]acetaldehyde (6.70 g, 31.5 mmol) was thenadded and the solution was stirred at reflux for 24 h. The solvent wasevaporated and 50 mL of water was added. The solid was collected andwashed with water to give 8.3 g (98%): MS m/z 251 (M−17+H).

Step 4

5-[4-(3-Chloro-propoxy)-phenyl]-2-pyridin-2-yl-2H-pyridazin-3-one

A solution of the product from step 3 (8.0 g, 29.8 mmol) and2-hydrazinopyridine (9.75 g, 3.0 mmol) in 80 mL of acetic acid wasstirred at 110° C. for 24 h. The solvent was evaporated and the residuewas purified with ISCO Combiflash chromatography with 2% MeOH inmethylene chloride. The product was crystallized from EtOH and ether togive 5.88 g (58%) of5-[4-(3-chloropropoxy)-phenyl)-5-hydroxy-5H-furan-2-one: Mp 219-220° C.;MS m/z 391 (M+H).

Step 5

5-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyridin-2-yl-2H-pyridazin-3-one

A mixture of the product from step 4, R-2-methyl-pyrrolidinebenzenesulfonic acid salt (12.0 g, 51.0 mmol), potassium carbonate (8.2g, 59.0 mmol) and sodium iodide (50 mg, 0.334 mmol) in 150.0 mL ofacetonitrile was heated to 80° C. for 24 h. The reaction mixture wasthen filtered, washed with methylene chloride (2×20 mL) andconcentrated. The residue was dissolved in 100 mL of methylene chlorideand washed with saturated NaHCO₃, saturated NaCl solution, dried overNa₂SO₄ and concentrated. The residue was purified by ISCO graduatesilica gel chromatography with 10% MeOH in CH₂Cl₂ with 0.5% of iPrNH₂ togive the product. The product was dissolved in MeOH and added 40.0 mL of1N HCl in EtOH and concentrated to dryness. Crystallization using MeOHand CH₃CN afforded the HCl salt (5.45 g, 75%) Mp 219-220° C.; MS m/z 391(M+H).

Example 95

5-[4-(3-Piperidin-1-yl-propoxy)-phenyl]-2-pyridin-2-yl-2H-pyridazin-3-one

This compound was prepared using the procedure for example 94 to givethe HCl salt; Mp 266-8° C.; MS m/z 391 (M+H).

Example 96

5-[4-(3-Azepan-1-yl-propoxy)-phenyl]-2-pyridin-2-yl-2H-pyridazin-3-one

This compound was prepared using the procedure for example 94 to givethe HCl salt; Mp 230-2° C.; MS m/z 405 (M+H).

Example 97

2-Methyl-5-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one Step1

5-[4-(3-Chloro-propoxy)-phenyl]-2H-pyridazin-3-one

A solution of the product from example 94 step 3 (2.0 g, 7.45 mmol) andhydrazine hydrate (0.59 g, 1.5 eq.) in 20 mL of EtOH was stirred at 85°C. for 2 h. The solvent was reduced and the solid was collected andwashed with cold EtOH to give 1.2 g (61%) of5-[4-(3-chloropropoxy)phenyl)-2H-pyridazin-3-one: Mp 197-9° C.; MS m/z265 (M+H).

Step 2

This compound was prepared from the product of step 1 (5.8 g, 17.0 mmol)and piperidine using the procedure for example 88. The hydrochloridesalt of the product was prepared; Mp 249-250° C.; MS m/z 314 (M+H).

Example 98

2-(6-Methyl-pyridin-2-yl)-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-oneStep 1

5-(4-Methoxy-phenyl)-2H-pyridazin-3-one

A suspension of 5-hydroxy-4-(4-methoxyphenyl)-5H-furan-2-one (2.00 g,9.7 mmol) in 15 mL of ethanol was stirred as hydrazine hydrate (0.97 g,2.0 eq) was added in dropwise. The reaction was stirred at 85° C.overnight, and then the solvent was reduced. The solid was collected andwashed with cold EtOH to give 1.7 g (87%) of5-(4-methoxy-phenyl)-2H-pyridazin-3-one: MS m/z 203 (M+H).

Step 2

5-(4-Methoxy-phenyl)-2-(6-methyl-pyridin-2-yl)-2H-pyridazin-3-one

A mixture of the product from step 1 (1.34 g, 6.62 mmol), copper (I)iodide (0.4 g, 2.0 mmol) and potassium carbonate (1.4 g, 9.9 mmol) inDMF (15 mL) was stirred and degassed with N₂ for 3 min. Then2-bromo-6-methylpyridine was added dropwise. After stirred at 120° C.overnight, the mixture was filtered through celite, washed with 50 mL ofCH₂Cl₂, 15% of NH₄OH solution (3×15 mL), water, saturated NaCl solution,and dried over Na₂SO4. The residue was purified by ISCO graduatechromatography (5% MeOH in CH₂Cl₂) to give5-(4-methoxyphenyl)-2-(6-methylpyridin-2-yl)-2H-pyridazin-3-one (0.30 g,15%): Mp 167-8° C.; MS m/z 294 (M+H).

Step 3

5-(4-Hydroxy-phenyl)-2-(6-methyl-pyridin-2-yl)-2H-pyridazin-3-one

This compound was prepared using the procedure described for Example 91step 3; MS m/z=280 (M+H).

Step 4

Example 98 was prepared from the product of step 3 using proceduresdescribed in Example 91 Step 4 and Step 5; Mp 118-120° C.; MS m/z 405(M+H).

Example 99

2-(3-Methyl-pyridin-2-yl)-5-{4-[3-((R)-2-methylpyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one

Example 99 was prepared as the hydrochloride salt using proceduresdescribed for Example 98; Mp 98-100° C.; MS m/z 405 (M+H).

Example 100

6-Methyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyridin-2-yl-2H-pyridazin-3-one

Example 100 was prepared as the hydrochloride salt using proceduresdescribed for Example 98; Mp 155-7° C.; MS m/z 405 (M+H).

Example 101

6-Methyl-2-(3-methyl-pyridin-2-yl)-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one

Example 101 was prepared as the hydrochloride salt using proceduresdescribed for Example 98; Mp 106° C. (dec.); MS m/z 419 (M+H).

Example 102 Step 1

4-[4-(2-Oxo-propyl)-phenoxy]-piperidine-1-carboxylic acid tert-butylester

A solution of triphenylphosphine (18.5 g, 70.6 mmol) and 40% DEAD intoluene (12.3 g, 70.6 mmol) in 125.0 mL of tetrahydrofuran was cooled to0° C. under N₂ as a solution of 1-(4-hydroxy-phenyl)-propan-2-one (6.54g, 43.6 mmol) and 4-hydroxy-piperidine-1-carboxylic acid tert-butylester (10.7 g, 53.2 mmol) in 125.0 mL of tetrahydrofuran was addeddropwise via addition funnel. After stirred at rt overnight, the solventwas evaporated. The residue was stirred in hexane/EtOAc, the solidformed was filtered. The hexane/EtOAC solution was concentrated andpurified by ISCO graduate chromatography (hexane-20% EtOAc in hexane) togive 4-[4-2-oxo-propyl)-phenoxy]-piperidine-1-carboxylic acid tert-butylester (8.52 g, 59%).

Step 2

4-[4-(3-Methyl-6-oxo-1,6-dihydro-pyridazin-4-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester

A mixture of 4-[4-(2-oxo-propyl)-phenoxy]-piperidine-1-carboxylic acidtert-butyl ester (7.01 g, 21.03 mmol) and glyoxalic acid hydrate (1.9 g,21 mmol) was heated to 100° C. for 5 h. The resulting dark thick oil wasstirred in 30 mL of EtOH as hydrazine hydrate (2.1 g, 42 mmol) wasadded. After stirred at 90° C. for 5 hr, the reaction was cooled to rt,and the solvent was evaporated. The crude product was purified by flashchromatography (10% MeOH in CH₂Cl₂), followed by trituration with etherto give4-[4-(3-methyl-6-oxo-1,6-dihydro-pyridazin-4-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester (3.25 g, 46%): Mp 184-6° C.; MS m/z 386 (M+H).

Example 102

6-Methyl-5-[4-(piperidin-4-yloxy)-phenyl]-2H-pyridazin-3-one;hydrochloride

A solution of the product from step 2(4-[4-(3-methyl-6-oxo-1,6-dihydro-pyridazin-4-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester) (7.6 g, 20 mmol) in 30 mL of dioxane and 3.0 mLof water was cooled to 0° C. as 24 mL of 4M HCl in dioxane was addeddropwise. After stirring at 50° C. for 1 h, the solvent was evaporated.The white solid was triturated with ether to give6-methyl-5-[4-(piperidin-4-yloxy)-phenyl]-2H-pyridazin-3-one HCl (6.2 g,92%): Mp 225-7° C.; MS m/z 286 (M+H).

Example 103

5-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-6-methyl-2H-pyridazin-3-one

A solution of example 102 (5.4 g, 18.9 mmol), sodium cyanoborohydride(2.4 g, 38 mmol) and cyclobutanone (6.6 g, 95 mmol) in 40.0 mL of DMF,80.0 mL of MeOH and 5.0 mL of acetic acid was stirred at 60° C. for 1 h.The reaction was cooled to rt, quenched with ice-water and the solventevaporated. The residue was diluted with 100 mL of CH₂Cl₂, washed withsaturated NaHCO₃ solution (3×30 mL), water (2×20 mL), NaCl solution (30mL) and dried over Na₂SO₄. The crude product was purified by Combiflashchromatography (CH₂Cl₂ to 10% MeOH in CH₂Cl₂ with 0.5% of iPrNH₂) togive the free base of the product. The product was then dissolved inMeOH and filtered. Then 30 mL of 1N HCl was added and the solutionevaporated. The hydrochloride salt was crystallized from MeOH and Et₂Oto give example 103 HCl (6.03 g, 90%): Mp 296-7° C.; MS m/z 340 (M+H).

Example 104 Step 1

5-(4-Methoxy-phenyl)-6-methyl-2H-pyridazin-3-one

5-(4-methoxyphenyl)-6-methyl-2H-pyridazin-3-one was prepared from1-(4-methoxy-phenyl)propan-2-one and glyoxalic acid and hydrazinehydrate using the procedure described in Example 86 Step 1; Mp 255-256°C.; MS m/z 203 (M+H).

Step 2

5-(4-Methoxy-phenyl)-6-methyl-2-pyridin-2-yl-2H-pyridazin-3-one

5-(4-Methoxy-phenyl)-6-methyl-2-pyridin-2-yl-2H-pyridazin-3-one wasprepared from 5-(4-methoxy-phenyl)-6-methyl-2H-pyridazin-3-one and2-bromopyridine in the presence of copper iodide using the proceduredescribed in Example 98 Step 2; Mp 156-7° C.; MS m/z 294 (M+H).

Step 3

5-(4-Hydroxy-phenyl)-6-methyl-2-pyridin-2-yl-2H-pyridazin-3-one

5-(4-Hydroxy-phenyl)-6-methyl-2-pyridin-2-yl-2H-pyridazin-3-one wasprepared from5-(4-Methoxy-phenyl)-6-methyl-2-pyridin-2-yl-2H-pyridazin-3-one and BBr₃in CH₂Cl₂ using the procedure described in Example 91 Step 3; Mp 252-4°C.; MS m/z 280 (M+H).

Step 4

4-[4-(3-Methyl-6-oxo-1-pyridin-2-yl-1,6-dihydro-pyridazin-4-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester

A mixture of5-(4-hydroxyphenyl)-6-methyl-2-pyridin-2-yl-2H-pyridazin-3-one (97.7 g,28 mmol), t-butyl 4-methanesulfonyloxypiperidine-1-carboxylic acid ester(15 g, 55 mmol) and cesium carbonate (18 g, 55 mmol) in 75 mL of DMF wasstirred at 100° C. overnight. The reaction mixture was cooled to rt,filtered through celite, and concentrated. The crude product was dilutedwith 100 mL of CH₂Cl₂, washed with 2N NaCO₃, water, NaCl solution, thendried over Na₂SO4, and concentrated. The product was purified by flashchromatography (5% MeOH in CH₂Cl₂) and triturated with EtOAc and hexaneto give4-[4-(3-methyl-6-oxo-1-pyridin-2-yl-1,6-dihydropyridazin-4-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester (6.7 g, 72%): MS m/z 463 (M+H).

Example 104

5-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-6-methyl-2-pyridin-2-yl-2H-pyridazin-3-one

This compound was prepared using the product from step 4 and theprocedures described in Example 103 Step 3 and Step 4; HCL salt mp285-6° C.; MZ m/z 417 (M+H).

Example 105 Step 1

4-[4-(2-Hydroxy-ethyl)-phenoxy]-piperidine-1-carboxylic acid tert-butylester

A mixture of 2-(4-hydroxyphenyl)ethanol (4.15 g, 30 mmol),4-methanesulfonyloxy-piperidine-1-carboxylic acid t-butyl ester (10.51g, 37.6 mmol) and cesium carbonate (19.6 g, 60 mmol) in 100 mL of DMFwas stirred at 100° C. overnight. The reaction mixture was cooled to rt,filtered through celite and concentrated. The crude product was dilutedwith 100 mL of CH₂Cl₂, washed with 2N Na₂CO₃, water, NaCl solution,dried over Na₂SO₄, and concentrated. The product was purified by flashchromatography (60% EtOAc in hexanes) to give4-[4-(2-hydroxy-ethyl)-phenoxy]-piperidine-1-carboxylic ester (8.2 g,59%): MS m/z 222 (M-Boc+H).

Step 2

4-[4-(2-Oxo-ethyl)-phenoxy]-piperidine-1-carboxylic acid tert-butylester

A solution of 4-[4-(2-hydroxyethyl)-phenoxy]piperidine-1-carboxylic acidtert-butyl ester (8.10 g, 25.2 mmol) in 90 mL of CH₂Cl₂ was cooled to 0°C. as Dess-Martin periodinane (11.2 g, 26.5 mmol) was added in portions.After stirred at rt overnight, the reaction was diluted with 100 mL ofCH₂Cl₂, and washed with saturated NaHCO₃ (5×100 mL), water, and driedover Na₂SO₄. Flash chromatography with 60% Et₂O in hexane gave 2.83 g(35%) of 4-[4-(2-oxo-ethyl)-phenoxy]-piperidine-1-carboxylic acidtert-butyl ester: MS m/z 220 (M-Boc+H).

Step 3

4-[4-(2-Hydroxy-5-oxo-2,5-dihydro-furan-3-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester

4-[4-(2-hydro-5-oxo-2,5-dihydro-furan-3-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester was prepared from4-[4-(2-oxo-ethyl)-phenoxy]-piperidine-1-carboxylic acid tert-butylester and glyoxalic acid hydrate using procedure described in Example 94Step 3; MS m/z 275 (M-Boc+H).

Step 4

4-[4-(6-Oxo-1,6-dihydro-pyridazin-4-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester

A solution of the product from step 3 (1.0 g, 2.7 mmol) and hydrazinehydrate (0.27 g, 5.3 mmol) in 12 mL of MeOH was stirred at 80° C.overnight. After being cooled to rt, the solvent was reduced and thesolid was filtered and washed with cold EtOH to give 0.63 g (57%) of4-[4-(6-oxo-1,6-dihydro-pyridazin-4-yl)-phenoxy]piperidine-1-carboxylicacid tert-butyl ester: Mp 222-3° C.; MS m/z 372 (M+H).

Example 105

5-[4-(Piperidin-4-yloxy)-phenyl]-2H-pyridazin-3-one

This compound was prepared using the procedure for example 102; Mp ° C.;MS m/z 272 (M+H).

Example 106

5-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-2H-pyridazin-3-one

This compound was prepared as the HCl salt using the procedure forexample 103; Mp 296-8° C.; MS m/z 326 (M+H).

Example 107

5-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-6-methyl-2-thiophen-3-yl-2H-pyridazin-3-one

This compound was prepared as the HCl salt using the procedure forexample 104; Mp 277-9° C.; MS m/z 422 (M+H).

Example 108

6-Methyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-thiophen-3-yl-2H-pyridazin-3-one

This compound was prepared as the HCl salt using the procedure forexample 98; Mp 212-3° C.; MS m/z 410 (M+H).

Example 109

5-{4-[3-((S)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyridin-2-yl-2H-pyridazin-3-one

Example 109 was prepared using the same procedure as Example 94 exceptusing S-2-methylpyrrolidine HCl; Mp 218-220° C.; MS m/z 391 (M+H).

Example 110 Step 1

4-[4-(3-Methyl-6-oxo-1,4,5,6-tetrahydro-pyridazin-4-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester

A solution of the intermediate from Example 102 step 1 (1.0 g, 3.0 mmol)in THF (10 mL) at −78° C. under N₂ was added KHMDS (0.5 M in toluene,9.0 mL) dropwise. After 30 min at −78° C., ethyl bromoacetate (0.75 g,4.5 mmol) was added drop wise. After 1 hr at −78° C., the reaction wasquenched with 1 N HCl (4.0 mL), diluted with 20 mL of EtOAc and thelayers separated. The EtOAc layer was washed with 5% NaHCO₃, NaClsolution, then dried over Na₂SO₄ and concentrated. To the crude solid in10 mL of EtOH was added hydrazine hydrate (0.22 g, 0.45 mmol) and thereaction then stirred at 85° C. for 2 h. The mixture was cooled to rt,the solvent was reduced and the solid was filtered and washed with coldEtOH to give 0.65 g (56%) of4-[4-(3-methyl-6-oxo-1,4,5,6-tetrahydro-pyridazin-4-yl)-phenoxyl]-piperidine-1-carboxylicacid tert-butyl ester: Mp 165-7° C.; MS m/z 288 (M-Boc+H).

5-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-6-methyl-4,5-dihydro-2H-pyridazin-3-one

Example 110 was prepared from the product of step 1 using proceduresdescribed in Example 102 and Example 103; Mp 178-9° C.; MS m/z 342(M+H).

Example 111 Step 1

4-(3-Chloro-propoxy)-benzoic acid ethyl ester

A suspension of 4-hydroxybenzoic acid ethyl ester (5.0 g, 30 mmol),1-bromo-3-chloropropane (7.1 g, 45 mmol) and potassium carbonate (14 g,100 mmol) in 50 mL of acetone using the procedure described in Example88 Step 1 gave the product as a clear oil.

Step 2

4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-benzoic acid ethyl ester

A mixture of the product from step 1 (6.5 g, 27 mmol),R-2-methylpyrrolidine benzene sulfonic acid (16 g, 67 mmol), potassiumcarbonate (11 g, 80 mmol) and sodium iodide (50 mg, 0.3 mmol) in 100 mLof acetonitrile was stirred at 80° C. overnight. The reaction mixturewas filtered through celite, washed with CH₂Cl₂, combined andconcentrated. The residue was dissolved in CH₂Cl₂, washed with saturatedNaHCO₃, water, saturated NaCl, then dried over Na₂SO₄ to give 7.5 g(96%) of 4-[3-R-2-methylpyrrolidin-1-yl-propoxy]benzoic acid ethylester; MS m/z 292 (M+H).

Step 3

1-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyridin-2-yl-ethanone

A solution of the product from step 2 (4.0 g, 14 mmol) and2-methylpyridine (2.6 g, 27 mmol) in 60 mL of THF was cooled to 0° C.,then LiHMDS (1.0 M, 27 mmol) was added dropwise. After addition, thereaction was stirred at 45° C. overnight. The reaction was quenched withice-water, extracted with CH₂Cl₂ (3×50 mL), combined, washed withsaturated NaHCO₃, water, then dried over Na₂SO₄. Flash chromatographyusing 10% MeOH in CH₂Cl₂ gave the product (3.7 g, 78%); Mp 40-42° C.; MSm/z 339 (M+H).

Step 4

4-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4-oxo-3-pyridin-2-yl-butyricacid ethyl ester

A mixture of sodium hydride (0.092 g, 3.8 mmoL) in 10 mL of DMSO wasstirred under N₂ as the product from step 3 (1.0 g, 3.8 mmol) in 5.0 mLof DMSO was added dropwise. After the reaction was stirred for 30 min, asolution of ethyl bromoacetate (0.64 g, 8.83 mmol) in 6.0 mL of toluenewas added dropwise, and the reaction was stirred at rt for 1 h. Thereaction was then quenched with NH₄Cl solution and the solvent wasevaporated. The residue was extracted with CH₂Cl₂ (3×20 mL), combined,washed with saturated NaHCO₃, saturated NaCl then dried over Na₂SO₄. Thecrude product was purified by flash chromatography using 10% MeOH inCH₂Cl₂ to give the product (0.65 g, 52%).

6-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one

A solution of the ester intermediate(4-{4-[3-R-2-methyl-pyrrolidin-1-yl)-phenyl}-4-oxo-3-pyridin-2-yl-butyricacid ethyl ester) (9.2 g, 22 mmol) and hydrazine hydrate (2.2 g, 43mmol) in 150 mL of EtOH was stirred at reflux overnight. Flashchromatography using 15% MeOH in CH₂Cl₂ with 0.5% of iPrNH₂ followed bytreatment of the product with 1N HCl in EtOH gave hydrochloride of6-{4-[3-R-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one(6.1 g, 71%); Mp 133° C. (dec.); MS m/z 393 (M+H).

Example 112

6-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-5-pyridin-2-yl-2H-pyridazin-3-one

A mixture of example 111 (0.39 g, 1.0 mmol) in 4.0 mL of water was addedsodium 3-nitrobenzenesulfonate (0.18 g, 0.78 mmol) and NaOH (0.12 g, 3.0mmol). The reaction was heated to 100° C. as 2.5 mL of EtOH was added tomake the reaction homogeneous. After 2 h at 100° C., the reaction wascooled to rt. 2N HCl was added to adjust pH to ˜6, then the reaction wasextracted with CH₂Cl₂ (3×20 mL), which was washed with saturated NaHCO₃,saturated NaCl, and then dried over Na₂SO₄. The product was purified bypreparative TLC using 10% MeOH in CH₂Cl₂ and 0.5% of iPrNH₂ to give theproduct. The hydrochloride salt was prepared by treating the free basewith 1N HCl in EtOH (0.14 g, 35%); Mp 234° C. (dec.); MS m/z 391 (M+H).

Example 113 Step 1

4-(4-Ethoxycarbonyl-phenoxy)-piperidine-1-carboxylic acid tert-butylester

4-(4-Ethoxycarbonylphenoxy)piperidine-1-carboxylic acid tert-butyl esterwas prepared from 4-hydroxybenzoic acid ethyl ester and4-hydroxypiperidine-1-carboxylic acid tert-butyl ester using theprocedure described in Example 103 step 1; Mp 76-78° C.; MS m/z 350(M+H).

Step 2

4-[4-(2-Pyridin-2-yl-acetyl)-phenoxy]-piperidine-1-carboxylic acidtert-butyl ester

A solution of 4-(4-ethoxycarbonylphenoxy)piperidine-1-carboxylic acidtert-butyl ester (3.5 g, 10 mmol) and 2-methylpyridine (1.9 g, 2.0 mmol)in 50 mL of THF was stirred at 0° C. as LiHMDS (1.0M, 22 mL) was addeddropwise. The reaction was stirred at 45° C. overnight, then quenchedwith ice-water and the solvent evaporated. The residue was extractedwith CH₂Cl₂ (3×30 mL), and the combined CH₂Cl₂ layers were washed withsaturated NaHCO₃, saturated NaCl solution, dried over Na₂SO₄, andconcentrated to give the product; Mp 138-140° C.; MS m/z 397 (M+H).

Step 3

4-[4-(3-Ethoxycarbonyl-2-pyridin-2-yl-propionyl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester

A mixture of sodium hydride (0.21 g, 8.8 mmoL) in 10 mL of DMSO wasstirred under N₂ as4-[4-(2-pyridine-2-yl-acetyl)-phenoxy]-piperidine-1-carboxylic acidtert-butyl ester (3.50 g, 8.83 mmol) in 15 mL of DMSO was addeddropwise. After 30 min, a solution of ethyl bromoacetate (1.47 g, 8.83mmol) in 8.0 mL of toluene was added dropwise. The reaction was stirredat rt for 2 h and then quenched with saturated NH₄Cl solution, and thesolvent was evaporated. The residue was extracted with CH₂Cl₂ (3×20 mL),combined, washed with saturated NaHCO₃, saturated NaCl solution anddried over Na₂SO₄. The crude product was purified by Combiflashchromatography (CH₂Cl₂ to 1% MeOH in CH₂Cl₂) to give the product (4.0 g,94%): Mp 118-120° C.; MS m/z 483 (M+H).

Step 4

4-[4-(6-Oxo-4-pyridin-2-yl-1,4,5,6-tetrahydro-pyridazin-3-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester

A solution of the product from step 3 (4.0 g, 8.3 mmol) and hydrazinehydrate (0.83 g, 16 mmol) in 30 mL of EtOH was stirred at 90° C.overnight. The yellow suspension was reduced to ˜15 mL of EtOH. Thesolid was collected and washed with cold EtOH to give the product (2.05g, 55%): Mp 213-214° C.; MS m/z 395 (M-tBu+H).

Example 113

6-[4-(Piperidin-4-yloxy)-phenyl]-5-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one

This compound was prepared from the product of step 4 using proceduresdescribed in Example 102 Step 3 MS m/z 351 (M+H).

Example 114

6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-5-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one

This compound was prepared using the procedure for Example 103; Mp 199°C. (dec); MS m/z 405 (M+H).

Example 115

6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-5-pyridin-2-yl-2H-pyridazin-3-oneStep 1

4-[4-(6-Oxo-4-pyridin-2-yl-1,6-dihydro-pyridazin-3-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester

A mixture of the product from Example 113 step 4 (0.3 g, 0.67 mmol) andcesium carbonate (0.65 g, 2 mmol) in 4.0 mL of DMSO was heated under airat 150° C. for 0.5 h. The reaction was cooled to rt, filtered, washedwith CH₂Cl₂ (3×15 mL) and combined. The CH₂Cl₂ solution was washed withsaturated NaHCO₃, water and dried over Na₂SO4. The crude product wascrystallized from MeOH and ether to give the Boc product; Mp 210-2° C.;MS m/z 449 (M+H).

6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-5-pyridin-2-yl-2H-pyridazin-3-onewas prepared from the product in step 1 using procedures described inExample 102 Step 3 and Example 103; Mp 203° C. (dec.); MS m/z 403 (M+H).

Example 116

6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-4-methyl-4,5-dihydro-2H-pyridazin-3-oneStep 1

4-(4-Hydroxy-phenyl)-2-methyl-4-oxo-butyric acid ethyl ester

A solution of 4-(4-methoxyphenyl)-2-methyl-4-oxobutyric acid (10 g, 45mmol) and 150 mL of 48% HBr in 20 mL of AcOH was heated to 100° C. for48 h. The solvent was evaporated and EtOH (3×30 mL) was added andevaporated to give 4-(4-methoxy-phenyl)-2-methyl-4-oxobutyric acid ethylester (9.96 g, 93%); MS m/z 259 (M+23).

Step 2

4-[4-(3-Ethoxycarbonyl-butyryl)-phenoxy]-piperidine-1-carboxylic acidtert-butyl ester

4-[4-(3-Ethoxycarbonyl-butyryl)-phenoxy]piperidine-1-carboxylic acidtert-butyl ester was prepared using procedure described in Example 102step 1; MS m/z 442 (M+23).

The final product6-[4-(1-cyclobutylpiperidin-4-yloxy)phenyl]-4-methyl-4,5-dihydro-2H-pyridazin-3-oneHCl was prepared from4-[4-(3-ethoxycarbonyl-butyryl)phenoxy]-piperidine-1-carboxylic acidtert-butyl ester using procedures described in Example 102 Step 3 andExample 103; Mp 257-9° C.; MS m/z 342 (M+H).

Example 117

5-[6-(1-Cyclobutyl-piperidin-4-yloxy)-pyridin-3-yl]-2H-pyridazin-3-oneStep 1

5-(6-Chloro-pyridin-3-yl)-2H-pyridazin-3-one

4,5-Dichloropyridazin-6-one (10 g, 60.6 mmol) and 57 wt. % hydroiodicacid in water (80 mL, 1.0 mmol) was heated to 150° C. for 24 h. Thereaction was cooled to rt, the solid was washed with sodium thiosulfate.The crude product was triturated with CH₂Cl₂:MeOH (1:1) and filtered togive 5-iodo-2H-pyridazin-3-one (4.64 g, 35%).

A mixture of 5-iodo-2H-pyridazin-3-one (4.64 g, 21 mmol) and 30%formaldehyde in water was heated to reflux for overnight. The reactionwas cooled to rt, and the resulting solid was filtered to give2-hydromethyl-5-iodo-2H-pyridazin-3-one (5.2 g, 99%).

A mixture of 2-hydromethyl-5-iodo-2H-pyridazin-3-one (1.15 g, 4.56 mmol)and 2-chloro-5-pyridineboronic acid (0.72 g, 4.57 mmol),tetrakis(triphenylphosphine)-palladium(0) (0.53 g, 0.46 mmol) andpotassium carbonate (1.89 g, 13.7 mmol) in 30 mL of 1,2-dimethoxyethaneand 10 mL of water was degassed for 3 min, then heated to 85° C.overnight. The reaction was cooled to rt, filtered and washed with ethylacetate. The organic layer was separated, concentrated, and trituratedwith ether to give 5-(6-chloro-pyridin-3-yl)-2H-pyridazin-3-one (0.4 g,36%); MS m/z 208 (M+H).

Step 2

4-[5-(6-Oxo-1,6-dihydro-pyridazin-4-yl)-pyridin-2-yloxy]-piperidine-1-carboxylicacid tert-butyl ester

A solution of 5-(6-chloropyridin-3-yl)-2H-pyridazin-3-one (73 mg, 0.35mmol) and 4-hydroxypiperidine-1-carboxylic acid tert-butyl ester (140mg, 0.70 mmol) in 2.7 mL of DMSO was stirred as KOtBu in2-methyl-2-propanol (1.0 M, 14.4 mL) was added dropwise. After stirringat 110° C. overnight, the reaction was cooled to rt, and 2 mL of waterwas added. The mixture was extracted with CH₂Cl₂ (3×10 mL), the extractscombined and dried over Na₂SO₄. The crude product was purified by prep.TLC with 10% MeOH in CH₂Cl₂ to give 71 mg (54%) of4-[5-(6-oxo-1,6-dihydropyridazin-4-yl)-pyridin-2-yloxy]piperidine-1-carboxylicacid tert-butyl ester; MS m/z 273 (M-Boc−H).

Example 117 hydrochloride was prepared from the product in step 2 usingprocedures described in Example 102 Step 3 and Example 103; Mp 232-4°C.; MS m/z 327 (M+H).

Example 118

2-(2-Fluoro-ethyl)-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-oneStep 1

2-(2-Fluoro-ethyl)-6-(4-methoxy-phenyl)-2H-pyridazin-3-one

A mixture of 6-(4-methoxyphenyl)-2H-pyridazin-3-one (170 mg, 0.83 mmol),1-bromo-2-fluoroethane (122.5 mg, 1.5 eq.), NaI (20 mg) and cesiumcarbonate (553 mg, 2.0 eq.) in 5 mL of CH₃CN was heated to 70° C.overnight. The reaction mixture was filtered and concentrated. Theproduct was purified by ISCO combiflash with 50% hexane and EtOAc togive 2-(2-fluoroethyl)-6-(4-methoxyphenyl)-2H-pyridazin-3-one (200 mg,97%); MS m/z 349 (M+H).

Example 118 hydrochloride was prepared from the product in step 1 usingprocedures described in Example 1 and example 86; mp 135-6° C.; MS m/z360 (M+H).

The following compounds were prepared as HCl salts unless noted usingmethods for example 1, example 11 or example 91.

Example Structure Mp (° C.) MS m/z 119

252-3  332 (M + H) 6-{3-Fluoro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 120

240-2  332 (M + H) 6-[3-Fluoro-4-(3-piperidin-1-yl-pro-poxy)-phenyl]-2H-pyridazin-3-one 121

201-3  330 (M + H) 4-Methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one 122

207-8  328 (M + H) 4-Methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 123

227-9  328 (M + H) 4-Methyl-6-[4-(3-piperidin-1-yl-pro-poxy)-phenyl]-2H-pyridazin-3-one 124

120-2  398 (M + H)4-{4-[3-((S)-2-Hydroxymethyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-methyl-5,6,7,8-tetrahydro-2H-phthalazin-1-one 125

172-4  368 (M + H)2-Methyl-4-{3-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2,5,6,7-tetrahydro-cyclopenta[d]pyridazin-1-one 126

189-190 368 (M + H) 2-Methyl-4-[3-(3-piperidin-1-yl-propoxy)-phenyl]-2,5,6,7-tetrahydro-cyclopenta[d]pyridazin-1-one 127

193-4  384 (M + H)4-{3-[3-((S)-2-Hydroxymethyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-methyl-2,5,6,7-tetrahydro-cyclopenta[d]pyridazin-1-one 128

251-3  356 (M + H) 2-Isopropyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 129

>200 dec. base 339 (M + H)2-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-5-(6-oxo-1,6-dihydro-pyridazin-3-yl)-benzonitrile 130

207-9  base 339 (M + H) 2-[3-(piperidin-1-yl)-propoxy]-5-(6-oxo-1,6-dihydro-pyridazin-3-yl)-benzonitrile 131

95-98 base 358 (M + H)2-(2-Hydroxy-ethyl)-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 132

163-7  base 328 (M + H) 6-{4-[(S)-2-Methyl-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxyl-phenyl}-2H-pyridazin-3-one 133

134 dec. base 354 (M + H) 4-[4-(3-Piperidin-1-yl-propoxy)-phenyl]-2,5,6,7-tetrahydro-cyclopenta[d]pyridazin-1-one 134

186 dec. base 314 (M + H) 6-[4-(3-Piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one 135

175 dec. base 344 (M + H) 6-[3-Methoxy-4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one 136

148 dec. base 344 (M + H) 6-{3-Methoxy-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 137

114 dec. base 328 (M + H) 6-[2-Methyl-4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one 138

>200 tartrate 392 (M + H)6-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyrimidin-2-yl-2H-pyridazin-3-one 168

76-78 base 398 (M + H)6-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-(2,2,2-trifluoro-ethyl)-4,5-dihydro-2H-pyridazin-3-one 169

87-89 base 398 (M + H)6-{4-[3-piperidin-1-yl-propoxy]-phenyl}-2-(2,2,2-tri-fluoro-ethyl)-4,5-dihydro-2H-pyridazin-3-one 170

121-123 base 396 (M + H)6-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-(2,2,2-trifluoro-ethyl)-2H-pyridazin-3-one 171

128-130 base 396 (M + H) 6-[4-(3-Piperidin-1-yl-propoxy)-phenyl]-2-(2,2,2-trifluoro-ethyl)-2H-pyridazin-3-one

Example 139

6-[6-(1-Cyclopentyl-piperidin-4-yloxy)-pyridin-3-yl]-2H-pyridazin-3-oneStep 1

6-(6-Chloro-pyridin-3-yl)-4,5-dihydro-2H-pyridazin-3-one

To ethyl-4-(4-chloro-3-pyridyl)-4-oxobutyrate (5 g, 20.7 mmol) inethanol (30 mL) was added hydrazine monohydrate (964 μM, 31 mmol). Afterovernight stirring at 80° C., the reaction was concentrated to half ofthe volume and the resulting yellow solid was filtered off and dried togive 3.4 g of product (77%); MS m/z 210 (M+H).

Step 2

4-[5-(6-Oxo-1,6-dihydro-pyridazin-3-yl)-pyridin-2-yloxy]-piperidine-1-carboxylicacid tert-butyl ester

To 6-(6-chloro-pyridin-3-yl)-4,5-dihydro-2H-pyridazin-3-one (3 g, 14.4mmol) in DMSO (40 mL) was added 4-hydroxy-boc-piperidine (2.9 g, 14.4mmol), followed by 1M KtOBu (19 mL). After overnight stirring at 100° C.open to air, the reaction was cooled, diluted with dichloromethane andwashed several times with water/brine, dried over sodium sulfate, andconcentrated under vacuum to obtain 4.9 g crude product (92%); MS m/z373 (M+H).

Step 3

6-[6-(Piperidin-4-yloxy)-pyridin-3-yl]-2H-pyridazin-3-one

To4-[5-(6-oxo-1,6-dihydro-pyridazin-3-yl)-pyridin-2-yloxy]-piperidine-1-carboxylicacid tert-butyl ester (4.9 g, 13.2 mmol) in dioxane (30 mL) was added 4NHCl/dioxane (6.6 mL, 3 mmol). After overnight stirring at 60° C., thereaction was concentrated under vacuum to obtain 4 g of product as theHCl salt (quantitative); MS m/z 327 (M+H).

Step 4 Example 139

6-[6-(1-Cyclopentyl-piperidin-4-yloxy)-pyridin-3-yl]-2H-pyridazin-3-one

6-[6-(piperidin-4-yloxy)-pyridin-3-yl]-2H-pyridazin-3-one hydrochloride(407 mg, 1.18 mmol) in a mixture of DMF (5 mL), methanol (15 mL), andacetic acid (250 μL) was added cyclopentanone (314 μL, 3.54 mmol),followed by sodium cyanoborohydride (371 mg, 5.9 mmol). After stirringat 60° C. for 2 h, the reaction was concentrated, partitioned betweendichloromethane/1N sodium carbonate, washed with water/brine, dried oversodium sulfate, and concentrated. The product was purified using prepTLC plates (9:1 dichloromethane:methanol) (25%); Mp 233-237° C.; MS m/z341 (M+H).

Example 140

6-[6-(1-Isopropyl-piperidin-4-ylmethoxy)-pyridin-3-yl]-2H-pyridazin-3-one

To the product from step 1 Example 139 (115 mg, 0.55 mmol) in DMSO (5mL) was added (1-isopropanol-piperidin-4-yl)methanol (130 mg, 0.83 mmol)and 1M KtOBu (1.1 mL, 1.1 mmol). After overnight stirring at 100° C.,the reaction was diluted with dichloromethane, washed with water/brineseveral times, dried over sodium sulfate, and concentrated. The productwas purified by prep TLC plates to obtain 64 mg (35%); Mp 188-191° C.;MS m/z 329 (M+H).

The following examples were prepared using methods for example 139

Example Structure Mp (° C.) MS m/z 141

217-219 327 (M + H) 6-[6-(1-Cyclobutyl-piperidin-4-yloxy)-pyridin-3-yl]-2H-pyridazin-3-one 142

195-197 315 (M + H) 6-[6-(1-Isopropyl-piperidin-4-yloxy)-pyridin-3-yl]-2H-pyridazin-3-one

Example 143

6-[6-(1-Cyclopentyl-piperidin-4-yloxy)-pyridin-3-yl]-2-methyl-2H-pyridazin-3-oneStep 1

6-(6-Chloro-pyridin-3-yl)-2-methyl-2H-pyridazin-3-one

To 6-(6-chloropyridin-3-yl)-4,5-dihydro-2H-pyridazin-3-one (1.03 g, 4.93mmol) in DMSO (40 mL) was added iodomethane (460 μL, 7.4 mmol) andcesium carbonate (3.2 g, 9.86 mmol). After overnight stirring at 100° C.open to air, the reaction was cooled, diluted with dichloromethane,washed several times with water/brine, dried over sodium sulfate, andconcentrated under vacuum to obtain 835 mg product (79%); MS m/z 222(M+H).

Step 2

4-[5-(1-Methyl-6-oxo-1,6-dihydro-pyridazin-3-yl)-pyridin-2-yloxy]-piperidine-1-carboxylicacid tert-butylester

To 6-(6-chloro-pyridin-3-yl)-2-methyl-2H-pyridazin-3-one (3 g, 13.6mmol) in toluene (50 mL) was added 4-hydroxy-boc-piperidine (2.7 g, 13.6mmol) and 1M KtOBu (16.3 mL, 16.3 mmol). After overnight stirring at 80°C., the reaction was concentrated, partitioned betweendichloromethane/1N sodium carbonate, washed with water/brine, dried oversodium sulfate, and concentrated. The product was purified by columnchromatography (99:1 dichloromethane:methanol) to obtain 2.7 g (51%); MSm/z 387 (M+H).

Example 143-145 were synthesized using Example 139 step 3 and step 4(deprotection and reductive amination) and Example 143 Step 1alkylation.

Example Structure Mp (° C.) MS m/z 143

154-157 355 (M + H) 6-[6-(1-Cyclopentyl-piperidin-4-yloxy)-pyridin-3-yl]-2-methyl-2H-pyridazin-3-one 144

175-180 341 (M + H) 6-[6-(1-Cyclobutyl-piperidin-4-yloxy)-pyridin-3-yl]-2-methyl-2H-pyridazin-3-one 145

113-115 369 (M + H) 6-[6-(1-Cyclobutyl-piperidin-4-yloxy)-pyridin-3-yl]-2-isopropyl-2H-pyridazin-3-one

Example 146

6-{6-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-pyridin-3-yl}-2H-pyridazin-3-oneStep 1

3-((R)-2-Methyl-pyrrolidin-1-yl)-propan-1-ol

To 3-chloro-1-propanol (1.00 g, 10.6 mmol) in 2-butanone (10.00 mL) wasadded R-2-methyl-pyrrolidine hydrochloride (1.93 g, 15.9 mmol),potassium carbonate (3.65 g, 26.44 mmol), and potassium iodide (1.76 g,10.6 mmol). After overnight stirring at 100° C., the reaction wasfiltered, partitioned between dichloromethane/water, washed with brine,dried over sodium sulfate, and concentrated under vacuum to obtain 495mg product (33%); MS m/z 144 (M+H).

6-{6-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-pyridin-3-yl}-2H-pyridazin-3-oneStep 2

To 6-(6-chloro-pyridin-3-yl)-4,5-dihydro-2H-pyridazin-3-one (599 mg,2.86 mmol) (step 1 example 139) in DMSO (15 mL) was added3-(R)-2-methylpyrrolidin-1-yl)-propan-1-ol (495 mg, 3.46 mmol) and 1MKOtBu (5.72 mL). After overnight stirring at 110° C. open to air, thereaction mixture was cooled and poured into water, extracted withdichloromethane, washed with brine, dried over sodium sulfate, andconcentrated. The product was purified using prep TLC plates (9:1dichloromethane:methanol) to obtain 68 mg; Mp 178-181° C.; MS m/z 315(M+H).

Example 147

6-[6-(3-Piperidin-1-yl-propoxy)-pyridin-3-yl]-2H-pyridazin-3-one

This compound was prepared using the intermediate from step 1 example139 and 3-piperidin-1-yl-propanol using methods described for example146; Mp 155-158° C. MS m/z 315 (M+H).

Example 148

6-[6-(1-Cyclobutyl-piperidin-4-yloxy)-pyridin-3-yl]-4,4-dimethyl-4,5-dihydro-2H-pyridazin-3-oneStep 1

4-(5-Acetyl-pyridin-2-yloxy)-piperidine-1-carboxylic acid tert-butylester

To 4-hydroxy-boc-piperidine (1.55 g, 7.71 mmol) in DMSO (12 mL) wasadded 1M KtOBu (8.36 mL), followed by 1-(6-chloropyridin-3-yl)ethanone(1.00 g, 6.43 mmol). After overnight stirring at 100° C., the reactionwas poured into water, extracted with dichloromethane, washed withbrine, dried over sodium sulfate, and concentrated. The product waspurified using a Single Step column (7:3 hexanes:ethyl acetate) toobtain 0.5 g (25%); MS m/z 321 (M+H).

Step 2

4-[5-(3-Ethoxycarbonyl-3-methyl-butyryl)-pyridin-2-yloxy]-piperidine-1-carboxylicacid tert-butyl ester

To 4-(5-acetyl-pyridin-2-yloxy)-piperidine-1-carboxylic acid tert-butylester (1.36 g, 4.24 mmol) in THF (15 mL) at −78° C. was added 0.5Mpotassium bis(trimethylsilyl)amide in toluene (17 mL) and stirred for 30min before adding 2-bromo-2-methyl-propionic acid ethyl ester (1.25 mL,8.49 mmol) at −78° C. After overnight stirring at r.t., the reaction wasquenched with 1N HCl, extracted with dichloromethane, washed withwater/brine, dried over sodium sulfate, and concentrated. The productwas purified using a Single Step column (7:3 hexanes:ethyl acetate) toobtain 0.458 g (25%); MS m/z 435 (M+H).

Step 3

4-[5-(5,5-Dimethyl-6-oxo-1,4,5,6-tetrahydro-pyridazin-3-yl)-pyridin-2-yloxy]-piperidine-1-carboxylicacid tert-butyl ester

To4-[5-(3-ethoxycarbonyl-3-methyl-butyryl-pyridin-2-yloxy]piperidine-1-carboxylicacid tert-butyl ester (0.318 g, 0.732 mmol) in 2-propanol (8 mL) wasadded hydrazine monohydrate (2 mL). After overnight stirring at 120° C.,the reaction was partitioned between dichloromethane/water, washed withbrine, dried over sodium sulfate, and concentrated under vacuum toobtain 0.235 mg product (80%); MS m/z 403 (M+H).

Step 4

4,4-Dimethyl-6-[6-(piperidin-4-yloxy)-pyridin-3-yl]-4,5-dihydro-2H-pyridazin-3-one

To4-[5-(5,5-dimethyl-6-oxo-1,4,5,6-tetrahydro-pyridazin-3-yl)-pyridin-2-yloxy]-piperidine-1-carboxylicacid tert-butyl ester (0.340 g, 0.845 mmol) in dichloromethane (5 mL)was added TFA (0.700 mL). After stirring at r.t. for ˜3 h, the reactionwas concentrated under vacuum to obtain product as the TFA salt(quantitative); MS m/z 303 (M+H).

Example 148 was prepared using the product from step 4 and cyclobutanoneusing the procedure for example 139 step 4; m 240-245; MS m/z 357 (M+H).

Example 149

6-[6-(1-Cyclobutyl-piperidin-4-yloxy)-pyridin-3-yl]-2-pyridin-2-yl-2H-pyridazin-3-oneStep 1

To example 141 (0.509 g, 1.56 mmol) in DMF (8 mL) was added potassiumcarbonate (0.431 g, 3.12 mmol), 2-bromopyridine (0.223 mL, 2.34 mmol),and copper(I) iodide (0.0297 g, 0.156 mmol). After stirring at 150° C.for 4 h, the reaction was cooled, diluted with dichloromethane, washedwith water/brine, dried over sodium sulfate, and concentrated. Theproduct was purified using Prep. TLC plates (9:1dichloromethane:methanol), dissolved in methanol with 1N HCl/ether (˜2mL) added, concentrated, and recrystallized from methanol/ether as theHCl salt to give 0.223 mg (33%); Mp 261-262° C.; MS m/z 404 (M+H).

Example 150 Step 1

4-(4-Hydroxy-phenyl)-4-oxo-butyric acid ethyl ester

To 4-(4-methoxy-phenyl)-4-oxo-butyric acid ethyl ester (4.5 g, 19.0mmol) was added 48% HBr (50 mL). After overnight stirring at 120° C.,the reaction was concentrated and ethanol was added several times andconcentrated to obtain 4.18 g product (94%); MS m/z 223 (M+H).

Step 2

4-[4-(3-Ethoxycarbonyl-propionyl)-phenoxy]-piperidine-1-carboxylic acidtert-butyl ester

To triphenylphosphine (2.48 g, 9.48 mmol) in THF (25 mL) was added 40%w/w DEAD in toluene (4.00 mL, 8.95 mmol) and the reaction was cooled at0° C. before adding a mixture of 4-hydroxy-boc-piperidine (1.44, 7.14mmol) and 4-(4-hydroxyphenyl)-oxo-butyric acid ethyl ester (1.3 g, 5.8mmol) in THF (25 mL). After overnight stirring at r.t., the reaction wasconcentrated and the product was purified using a Single Step column(7:3 hexanes:ethyl acetate) to obtain 2.17 g (91%); MS m/z 406 (M+H).

Step 3

4-[4-(6-Oxo-1,4,5,6-tetrahydro-pyridazin-3-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester

To 4-[4-(3-ethoxycarbonyl-propionyl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester (2.68 g, 6.61 mmol) in 2-propanol (25 mL) wasadded hydrazine monohydrate (0.662 g, 13.2 mmol). After overnightstirring at 120° C., the reaction was concentrated down, partitionedbetween dichloromethane/water, washed with brine, dried over sodiumsulfate, and concentrated under vacuum to obtain 2.18 g product (88%);MS m/z 374 (M+H).

Example 150

6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one

6-[4-(piperidin-4-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-onetrifluoroacetate was prepared using conditions for Example 148 step 4.

To 6-[4-(piperidin-4-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-onetrifluoroacetate (6.50 g, 23.8 mmol) in DMF (10 mL), methanol (50 mL),and acetic acid (2 mL) was added cyclobutanone (5.33 mL, 71.3 mmol) andsodium cyanoborohydride (7.47 g, 119 mmol) in portions. After stirringat 60° C. for 4 h, the reaction was concentrated, diluted withdichloromethane, washed with water/brine, dried over sodium sulfate, andconcentrated. The product was purified using a Single Step column (9:1dichloromethane:methanol) and recrystallized from chloroform/ether toobtain 2.2 g (40%); Mp=196-198° C.; MS m/z 328 (M+H).

Examples 151-153 were synthesized using procedures for Example 150.

Example Structure Mp (° C.) MS m/z 150

196-198 328 (M + H) 6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one 151

195-197 346 (M + H) 6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-3-fluoro-phenyl]-4,5-dihydro-2H-pyridazin-3-one 152

157-158 356 (M + H) 6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-4,4-dimethyl-4,5-dihydro-2H-pyridazin-3-one 153

147-149 374 (M + H) 6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-3-fluoro-phenyl]-4,4-dimethyl-4,5-dihydro-2H-pyridazin-3-one

Example 154

6-[4-(1-Cyclopentyl-piperidin-4-yloxy)-phenyl]-2H-pyridazin-3-one

To example 150 (130 mg, 3.81 mmol) in DMSO (3 mL) was added cesiumcarbonate (248 mg, 7.61 mmol). After stirring at 130° C. for 2 h open toair, the reaction was filtered, diluted with dichloromethane, washedwith water/brine, dried over sodium sulfate, and concentrated. Theproduct was purified using Prep. TLC plates (9:1dichloromethane:methanol) to obtain 48 mg (37%); Mp 211-213° C.; MS m/z340 (M+H).

Examples 155-156 were synthesized using methods for example 154.

Example Structure Mp (° C.) MS m/z 154

211-213 340 (M + H) 6-[4-(1-Cyclopentyl-piperidin-4-yloxy)-phenyl]-2H-pyridazin-3-one 155

215-220 326 (M + H) 6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-2H-pyridazin-3-one 156

236-238 344 (M + H) 6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-3-fluoro-phenyl]-2H-pyridazin-3-one

Example 157

To example 150 (1.50 g, 4.58 mmol) in DMSO (20 mL) was added potassiumcarbonate (1.90 g, 13.7 mmol), 2-bromopyridine (0.872 mL, 9.16 mmol),and copper(I) iodide (0.0872 g, 0.458 mmol). After overnight stirring at150° C. open to air, the reaction was filtered, diluted withdichloromethane, washed with water/brine, dried over sodium sulfate, andconcentrated. The product was purified using a single step column (9:1dichloromethane:methanol), dissolved in methanol and 1N HCl/ether (˜2mL) was added, concentrated, and the product was recrystallized frommethanol/ether as the HCl salt to obtain 53 mg; Mp>240° C. (dec.); MSm/z 403 (M+H).

Example 158 Step 1

6-[4-(Piperidin-4-yloxy)-phenyl]-2-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one

To 4-[4-(3-carboxy-propionyl)-phenoxy]-piperidine-1-carboxylic acidtert-butyl ester (1.34 g, 3.55 mmol) in acetic acid (20 mL) was added2-hydrazinopyridine (1.94 g, 17.8 mmol). After overnight stirring at120° C., the reaction was concentrated under vacuum and the product waspurified using a Single Step column (9:1 dichloromethane:methanol) toobtain 295 mg; MS m/z 351 (M+H).

6-[4-(1-Cyclobutyl-piperidin-4-yloxy)phenyl]-2-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one

Example 158 was synthesized from the product in step 1 by reductiveamination described for example 150 and forming the HCl salt; Mp 263-265MS m/z 405 (M+H).

Examples 159-167 were prepared using methods described for examples150-157.

Example Structure Mp (° C.) MS m/z 159

184-6  342 (M + H) 6-[4-((R)-1-Cyclohexyl-pyrrolidin-3-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one 160

200-2  340 (M + H) 6-[4-((R)-1-Cyclohexyl-pyrrolidin-3-yloxy)-phenyl]-2H-pyridazin-3-one 161

— 311 (M + H) 6-[4-((R)-1-Cyclobutyl-pyrrolidin-3-yloxy)-phenyl]-2H-pyridazin-3-one 162

— 328 (M + H) 6-[4-((R)-1-Cyclopentyl-pyrrolidin-3-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one 163

120-123 382 (M + H) 2-Cyclobutyl-6-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one 164

100-104 396 (M + H) 2-Cyclobutyl-6-[4-(1-cyclopentyl-piperidin-4-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one 165

168-170 328 (M + H) 2-Cyclobutyl-6-[4-(piperidin-4-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one 166

146-147 410 (M + H) 6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-2-(2,2,2-trifluoro-ethyl)-4,5-dihydro-2H-pyridazin-3-one 167

225-227 424 (M + H) 6-[4-(1-Cyclopentyl-piperidin-4-yloxy)-phenyl]-2-(2,2,2-trifluoro-ethyl)-4,5-dihydro-2H-pyridazin-3-one

Example 172

5-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.2.0]oct-4-en-2-oneStep 1

2-(4-Methoxy-benzoyl)-cyclobutanecarboxylic acid

To 3-oxabicyclo[3.2.0]heptane-2,4-dione (8.00 g, 63.4 mmol) in THF(90.00 mL) at −78° C. was added 0.500 M of p-anisyl magnesium bromide(133 mL, 66.6 mmol) in THF (90 mL) dropwise. After stirring at −78° C.for 2 h, the reaction was quenched with ice cold water and concentrated.The aqueous layer was acidified and the white solid was filtered off anddried to obtain 9.72 g product (65%); MS m/z 233 (M−H).

Step 2

2-(4-Hydroxy-benzoyl)-cyclobutanecarboxylic acid ethyl ester

To 2-(4-methoxy-benzoyl)-cyclobutanecarboxylic acid (10.28 g, 43.88mmol) was added 48% hydrogen bromide in water (50 mL) and acetic acid(50 mL). After overnight stirring at 120° C., the reaction wasconcentrated, stirred with ethanol a few times, and the product waspurified using a Single Step column (7:3 hexanes:ethyl acetate) toobtain 7.70 g (71%); MS m/z 247 (M−H)

Example 172 HCl was synthesized from the product in step 2 usingprocedures described for example 150; Mp 285-288° C.; MS m/z 354 (M+H)

Example 173

5-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.2.0]oct-4-en-2-oneStep 1

2-[4-(3-Chloro-propoxy)-benzoyl]-cyclobutanecarboxylic acid ethyl ester

To 2-(4-hydroxy-benzoyl)-cyclobutanecarboxylic acid ethyl ester (0.55 g,2.20 mmol) in acetone (10 mL) was added potassium carbonate (0.91 g,6.58 mmol) and 1-bromo-chloropropane (0.26 mL, 2.63 mmol). Afterovernight stirring at 70° C., the reaction was filtered, partitionedbetween dichloromethane/water, washed with brine, dried over sodiumsulfate, and concentrated. The product was purified using a Single Stepcolumn (9:1 hexanes:ethyl acetate) to obtain 0.30 g (42%); MS m/z 325(M+H).

Step 2

2-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-benzoyl}-cyclobutanecarboxylicacid ethyl ester

To 2-[4-(3-chloro-propoxy)-benzoyl]-cyclobutanecarboxylic acid ethylester (0.300 g, 0.924 mmol) in acetonitrile (15 mL) was added(R)-2-methyl-pyrrolidine, benzenesulfonic acid salt (0.337 g, 1.38mmol), potassium carbonate (0.383 g, 2.77 mmol), and potassium iodide(0.153 g, 0.924 mmol). After overnight stirring at 80° C., the reactionwas filtered, diluted with dichloromethane, washed with water/brine,dried over sodium sulfate, and concentrated. The product was purifiedusing a Single Step column (5% methanol/dichloromethane) to obtain 0.213g (62%); MS m/z 374 (M+H).

Example 173 was synthesized using methods described for example 1 andexample 11.

Example 176

4-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-2,5,6,7-tetrahydro-cyclopenta[d]pyridazin-1-one

To example 174 (0.500 g, 1.36 mmol) in DMSO (5 mL) was added cesiumcarbonate (0.887 g, 2.72 mmol). After overnight stirring at 140° C. opento air, the reaction was poured into water, extracted withdichloromethane, washed with water/brine, dried over sodium sulfate, andconcentrated. The product was purified using Prep. TLC plates (9:1dichloromethane:methanol); Mp=210-213° C.; MS m/z 366 (M+H).

Example Structure Mp (° C.) MS m/z 172

285-288 354 (M + H) 5-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.2.0]oct-4-en-2-one 173

218-220 342 (M + H) 5-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.2.0]oct-4-en-2-one 174

dec. > 255 368 (M + H) 4-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl)-2,4a,5,6,7,7a-hexahydro-cyclopenta[d]pyridazin-1-one 175

218-219 356 (M + H)4-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2,4a,5,6,7,7a-hexahydro-cyclopenta[d]pyridazin-1-one 176

210-213 366 (M + H) 4-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-2,5,6,7-tetrahydro-cyclopenta[d]pyridazin-1-one

Example 177

2-Cyclobutyl-6-[6-(1-cyclobutyl-piperidin-4-yloxy)-pyridin-3-yl]-4,5-dihydro-2H-pyridazin-3-one

This compound was prepared usingethyl-4-(4-chloro-3-pyridyl)-4-oxobutyrate and cyclobutyl hydrazineusing methods described for examples 139 and 143; Mp 146-49 MS m/z 384(M+H).

Example 178 Method A

6-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one

Step 1 4-(4-Hydroxy-phenyl)-4-oxo-butyric acid ethyl ester (3.0 g, 13.5mmol), 1-bromo-3-chloropropane (4.2 g, 27 mmol) and K₂CO₃ (5.6 g, 41mmol) in acetonitrile (50 mL) was stirred at reflux for 12 h. Thereaction was filtered, concentrated and purified by silica gelchromatography to give 3.2 g (80%).

Step 2

4-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4-oxo-butyricacid ethyl ester

The product from step 1 (3.1 g, 10.4 mmol), R-2-methylpyrrolidine HCl(2.5 g, 21 mmol), KI (0.9 g) and K2CO3 (4.1 g, 2.9 mmol) in acetonitrile(75 mL) was stirred at 90° C. for 2 days. The reaction was cooled,filtered and concentrated. The residue was dissolved in Et2O (75 mL) andwashed with water and NaCL solution, dried (MgSO4) and concentrated toan oil; MS m/e 348 (M+H).

Step 3

6-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one

The product from step 2 (3.0 g, 8.6 mmol) and hydrazine hydrate (0.33 g,10 mmol) in isopropanol (50 mL) was stirred at 95° C. for 24 h. Thereaction was cooled to rt, concentrated and the product recrystallizedfrom EtOAc-hexane; Mp 142-45; MS m/z 316 (M+H).

The examples in the following table were synthesized using conditionsfor example 178 starting with4-(4-hydroxy-phenyl)-2,2-dimethyl-4-oxo-butyric acid ethyl ester or4-(3-fluoro-4-hydroxy-phenyl)-4-oxo-butyric acid ethyl ester.

Example Structure Mp (° C.) MS m/z 179

140-2  base 344 (M + H) 4,4-Dimethyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one 180

132-3  base 334 (M + H)6-{3-Fluoro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one 181

164-166 base 334 (M + H)6-[3-Fluoro-4-(3-piperidin-1-yl-propoxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one

Example 182

5,5-Dimethyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-oneStep 1

4-(4-Benzyloxy-phenyl)-3,3-dimethyl-4-oxo-butyric acid ethyl ester

(4-Benzyloxy-phenyl)-trimethylsilanyloxy-acetonitrile (3.0 g, 9.63 mmol)in THF (100 mL) under a nitrogen atmosphere was added LDA (7.2 mL of 2 Min THF) at −72° C. After 0.5 h, methyl 3-methylbut-2-enoate (1.23 mL,10.1 mmol) in 1 THF (15 mL) was added dropwise. The reaction was stirredat 0° C. for 4 h, and then saturated NH4Cl was added. The THF wasremoved at reduced pressure; Et2O was added (50 mL) and washed withsaturated NH4Cl, water, dried (Na2SO4), and concentrated to give an oil.The oil was dissolved in THF (50 mL) and TBAF (10.1 mL of 1 M THFsolution) was added at 0° C. dropwise. After stirring 12 h at rt thereaction was concentrated, dissolved in Et2O and washed with water, NaClsolution and dried (MgSO4). The product was purified by silica gelchromatography (10-20% EtOAc/hexanes) to give 1.5 g; Mp 72-73.

Step 2

4-(4-Hydroxy-phenyl)-3,3-dimethyl-4-oxo-butyric acid ethyl ester

The product from step 1 (1.25 g, 3.83 mmol) and 10% Pd/C (0.3 g) in MeOH(50 mL) was hydrogenated on a Parr apparatus until TLC indicatedcompletion of the reaction. The mixture was filtered, concentrated to anoil and used directly in the next step; MS m/z 204 (M-OMe).

Step 3

4-[4-(3-Chloro-propoxy)-phenyl]-3,3-dimethyl-4-oxo-butyric acid ethylester

The product from step 2 (1.0 g, 4.2 mmol), 1-bromo-3-chloropropane (1.0g, 8 mmol) and K₂CO₃ in acetonitrile (20 mL) was heated to reflux for 24h. The reaction was cooled, filtered, concentrated to an oil andpurified by ISCO silica gel chromatography (10% EtOAc/hexanes) to give0.7 g.

Step 4

3,3-Dimethyl-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4-oxo-butyricacid ethyl ester

The product from step 3 (0.75 g, 2.4 mmol), R-2-methylpyrrolidinebenzene sulfonic acid salt (1.0 g, 5 mmol), K2CO3 (1 g, 7 mmol) and KI(0.1 g) in acetonitrile (25 mL) were heated at 90° C. for 2 days. Thereaction was filtered, concentrated, dissolved in Et2O and washed withwater, NaCl solution and dried (MgSO₄) to give 0.7 g as an oil; MS m/z376 (M+H).

Example 182 Step 5

5,5-Dimethyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one

The product from step 4 (0.75 g, 2.1 mmol) and hydrazine hydrate (2.0mL) in acetonitrile (25 mL) were heated to reflux for 24 h. The reactionwas cooled, concentrated and the product recrystallized usingEt₂O-hexanes to give 600 mg (71%); Mp 118-121; MS m/z 344 (M+H).

Example 183

6-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-oneStep 1

6-(4-Methoxy-phenyl)-2-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one

In a 1 neck round bottom flask equipped with a Dean-Stark trap andcondenser, 4-(4-methoxyphenyl)-4-oxo-butyric acid (5.0 g, 20 mmol),2-hydrazinopyridine (3.9 g, 36 mmol) and p-toluene sulfonic acid (0.3 g)in 100 mL benzene were heated to reflux for 2 h while water was removed.The reaction was cooled to rt, an equal volume of Et₂O was added and theproduct collected; Mp>300° C. This solid was dissolved in HOAc (50 mL)and heated at 100° C. for 6 h. The reaction was concentrated, dissolvedin EtOAc and washed with saturated NaHCO₃ solution, water, NaCl solutionand dried (MgSO₄). The solvent was concentrated to a thick oil; MS m/z282 (M+H).

Step 2

6-(4-Hydroxy-phenyl)-2-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one

The product from step 1 (1.25 g, 4.4 mmol) in DCM (30 mL) was added BBr₃(30 mL, 1 M in DCM) dropwise at 0° C. After stirring 4 h at rt, themixture was cooled to 0-5° C. on an ice-bath while saturated NH₄Clsolution (30 mL) was added dropwise. Additional water was added and theDCM was removed at reduced pressure. The solid was collected and driedto give 1.1 g (93%) of a tan solid; Mp>220° C.; MS m/z 268 (M+H).

Step 3

6-[4-(3-Chloro-propoxy)-phenyl]-2-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one

The product from step 3 (5.0 g, 20 mmol), 1-bromo-3-chloropropane (5.9g, 37.4 mmol) and K₂CO₃ (7.8 g, 56 mmol) in acetonitrile (50 mL) washeated to reflux for 24 h. The reaction was cooled to rt, filtered andconcentrated to a thick oil. The product was dissolved in EtOAc andwashed with water, NaCl solution and dried (MgSO₄). The product waspurified by ISCO silica gel chromatography (95/5/1DCM/MeOH/i-propylamine) to give 3.7 g of a dark oil; MS m/z 344 (M+H).

Example 183 Step 4

6-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one

The product from step 3 (3.7 g, 10.8 mmol), R-2-methylpyrrolidinebenzene sulfonic acid salt (5.24 g, 21.5 mmol), K₂CO₃ (4.46 g, 32.3mmol) and KI (0.9 g) in acetonitrile (50 mL) were heated to reflux for 2days. The reaction was cooled, filtered and concentrated. The residuewas purified by ISCO silica gel chromatography (95/5/1DCM/MeOH/i-propylamine). The fractions were concentrated and the HClsalt was prepared using 2M HCl/ether and recrystallized fromCH₃CN/ether; Mp 203-205° C.; MS m/z 393 (M+H).

Example 184

6-{3,5-Difluoro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-oneStep 1

1-(3,5-Difluoro-4-hydroxy-phenyl)-ethanone

A mixture of 1-(3,5-difluoro-4-methoxyphenyl)ethanone (12 g, 64.5 mmol)and 48% aqueous HBr (32 mL) was stirred at reflux for 30 h. The reactionwas cooled to rt and diluted with water and the aqueous layer wasextracted twice with methylene chloride. The combined organics weredried (Na₂SO₄), filtered, and concentrated to give1-(3,5-difluoro-4-hydroxyphenyl)ethanone (10 g, 91%), mp 141-143° C.; MSm/z 171 (M−H).

Step 2

1-[4-(3-Chloro-propoxy)-3,5-difluoro-phenyl]-ethanone

A mixture of 1-(3,5-difluoro-4-hydroxyphenyl)ethanone (8.1 g, 47 mmol),3-bromo-1-chloropropane (14.7 g, 93 mmol) and K₂CO₃ (21.3 g, 154 mmol)in acetone (120 mL) was stirred at reflux for 20 h. The reaction wascooled to rt and concentrated at reduced pressure, then partitionedbetween water and methylene chloride. The aqueous layer was extractedtwice with methylene chloride to obtain1-[4-(3-chloropropoxy)-3,5-difluoro-phenyl]ethanone (12.9 g,quantitative yield); MS m/z 249 (M+H).

Step 3

6-[4-(3-Chloro-propoxy)-3,5-difluoro-phenyl]-2H-pyridazin-3-one

A mixture of 1-(4-(3-chloropropoxy)-3,5-difluoro-phenyl]ethanone (11 g,44.7 mmol) and glyoxalic acid monohydrate (4.2 g, 46.5 mmol) in aceticacid (16 mL) was stirred at 100° C. for 4 h. The acetic acid wasevaporated at reduced pressure and diluted with water then cooled to 0°C. and neutralized with ammonium hydroxide to pH 8. To this mixture,hydrazine monohydrate (4.3 mL, 86 mmol) was added and heated at 100° C.for 1 h. The reaction was cooled to rt and the solid was filtered, thendried to give a crude product. The crude product was trituratedsequentially with 5% aqueous sodium bicarbonate solution and with amixture of methylene chloride, methanol, ether and hexane to providerelatively pure product. The product was purified by ISCO (120 g silicagel column) chromatography using 2 to 8% methanol in methylene chlorideto furnish 6-[4-(3-chloropropoxy)-3,5-difluorophenyl]-2H-pyridazin-3-one(7.9 g, 59%), MS m/z 301 (M+H).

Step 4

6-{3,5-Difluoro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one

A mixture of6-[4-(3-chloropropoxy)-3,5-difluorophenyl]-2H-pyridazin-3-one (7.9 g,26.3 mmol), K₂CO₃ (12.7 g 91.9 mmol), NaI (144 mg, 0.96 mmol) andR-methyl-pyrrolidinium benzenesulfonate (13.4 g, 55.3 mmol) in CH₃CN(200 mL) was heated under argon at 80° C. for 35 h. The mixture wasfiltered over celite and concentrated at reduced pressure andpartitioned between saturated aqueous sodium bicarbonate solution andmethylene chloride. The aqueous layer was extracted twice with methylenechloride and the combined organics were washed with brine, dried(Na₂SO₄), and concentrated. The crude product was purified by ISCO (120g silica gel column) chromatography using 2 to 5% methanol in methylenechloride to 10% methanol containing 0.25% ammonium hydroxide inmethylene chloride to obtain6-{3,5-difluoro-4-[3-(R)-2-methylpyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one(4.3 g). The product was precipitated using a mixture of ethanol andacetonitrile to provide a pure product (0.5 g). Mp 169-171° C.; MS m/z350 (M+H).

Example 185

6-{3,5-Dibromo-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one

Example 185 was synthesized using the procedure for example 184; Mp165-167° C.; MS m/z 472 (M+H).

Example 186

6-{3,5-Difluoro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-oneStep 1

4-(3,5-Difluoro-4-methoxy-phenyl)-4-oxo-butyric acid ethyl ester

A mixture of 1,3-difluoro-2-methoxybenzene (2.5 g, 17.3 mmol) and ethylsuccinyl chloride (4.29 g, 26 mmol) in 1,2-dichloroethane (25 mL) wascooled to 0° C. Aluminum chloride (8 g, 60.1 mmol) was added slowly at0° C. then stirred at rt for 2 h and quenched with ice and aqueous 2NHCl at 0° C. The aqueous layer was extracted twice with methylenechloride and the combined organics were washed with brine, dried(Na₂SO₄), filtered, and concentrated to provide a crude product. Thecrude product was purified by ISCO (80 g silica gel column)chromatography using 8.5% EtOAc in hexane to furnish4-(3,5-difluoro-4-methoxyphenyl)-4-oxo-butyric acid ethyl ester (2.9 g,61%),

Step 2

4-(3,5-Difluoro-4-hydroxy-phenyl)-4-oxo-butyric acid ethyl ester

A mixture of 4-(3,5-difluoro-4-methoxy-phenyl)-4-oxo-butyric acid ethylester (2.9 g, 10.6 mmol) and 48% aqueous HBr (15 mL) in acetic acid (30mL) was stirred at reflux for 8 h. The reaction was cooled to rt andtreated three times with ethanol and then concentrated at reducedpressure to provide a crude material. The crude material was dissolvedin methylene chloride and washed with water, brine, dried (Na₂SO₄),filtered, and concentrated to afford4-(3,5-difluoro-4-hydroxyphenyl-4-oxo-butyric acid ethyl ester (2.5 g,92%), MS m/z 257 (M+H).

Step 3

4-[4-(3-Chloro-propoxy)-3,5-difluoro-phenyl]-4-oxo-butyric acid ethylester

A mixture of 4-[4-(3-chloropropoxy))-4-oxo-butyric acid ethyl ester (2.5g, 9.6 mmol), 3-bromo-1-chloropropane (1.9 mL, 18.5 mmol) and K₂CO₃ (4g, 28.9 mmol) in acetone (25 mL) was stirred at reflux for 15 h. Thereaction was cooled to rt and concentrated at reduced pressure, thenpartitioned between water and methylene chloride. The aqueous layer wasextracted twice with methylene chloride and the combined organics werewashed with brine, dried (Na₂SO₄), filtered, and concentrated to obtaina crude product. The crude product was purified by ISCO (80 g silica gelcolumn) chromatography using 10 to 12.5% EtOAc in hexane to provide4-[4-(3-chloro-propoxy)-3,5-difluoro-phenyl]-4-oxo-butyric acid ethylester (3.1 g, 96%).

Step 4

4-{3,5-Difluoro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4-oxo-butyricacid ethyl ester

A mixture of 4-[4-(3-chloropropoxy)-3,5-difluorophenyl]-4-oxo-butyricacid ethyl ester (5 g, 14.9 mmol), K₂CO₃ (7.2 g, 52.1 mmol), NaI (220mg, 1.4 mmol), and Benzenesulfonate; (R)-methylpyrrolidinium (8 g, 33mmol) in CH₃CN (110 mL) was heated under argon at 80° C. for 36 h. Thereaction was concentrated and partitioned between saturated aqueoussodium bicarbonate solution and methylene chloride. The aqueous layerwas extracted twice with methylene chloride and the combined organicswas washed with brine, dried (Na₂SO₄), filtered, and concentrated toprovide a crude material (96% purity). The crude material was purifiedby ISCO (80 g silica gel column) chromatography using 2% to 9% methanolin methylene chloride to 10% methanol containing 0.1% ammonium hydroxidein methylene chloride. The isolated material was dissolved in methylenechloride and washed with saturated aqueous sodium bicarbonate solution,brine, dried (Na₂SO₄), filtered, and concentrated. The isolated materialwas crystallized with a mixture of methylene chloride, ether and hexaneto obtain4-{3,5-difluoro-4[3-(R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4-oxo-butyricacid ethyl ester (3.97 g, 70%, 99% purity), MS m/z=384 (M+H).

Step 5

6-{3,5-Difluoro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one

A mixture of4-{3,5-difluoro-4[3-(R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4-oxo-butyricacid ethyl ester (3.97 g, 10.4 mmol) and hydrazine monohydrate (1 mL,20.7 mmol) in isopropanol (25 mL) was heated at 110° C. for 17 h.Isopropanol was evaporated at reduced pressure and partitioned betweensaturated aqueous sodium bicarbonate solution and methylene chloride.The aqueous layer was extracted twice with methylene chloride and thecombined organics was washed with brine, dried (Na₂SO₄), filtered, andconcentrated to provide a crude material. The crude material waspurified by ISCO (80 g) chromatography using 2 to 8% methanol inmethylene chloride to 10% methanol containing 0.2% ammonium hydroxide inmethylene chloride. The isolated material was dissolved in methylenechloride and washed with saturated aqueous sodium bicarbonate solution,brine, dried (Na₂SO₄), filtered, and concentrated. The pure material wascrystallized using a mixture of methylene chloride, ether and hexane toobtain6-{3,5-difluoro-4-[3-(R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one(2 g, 55%, 98% purity), mp 102-104° C., MS m/z 352 (M+H).

Example 187

6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-3,5-difluoro-phenyl]-4,5-dihydro-2H-pyridazin-3-oneStep 1

4-[4-(3-Ethoxycarbonyl-propionyl)-2,6-difluoro-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester

To a solution of triphenylphosphine (5.79 g, 22.1 mmol) in THF (35 mL)was added 40% w/w DEAD in toluene (10 mL, 15 mmol). The mixture wascooled to 0° C. and a mixture of4-(3,5-difluoro-4-hydroxy-phenyl)-4-oxo-butyric acid ethyl ester(example 186 step 2) (3.8 g, 14.7 mmol) and4-hydroxy-piperidine-1-carboxylic acid tert-butyl ester (3.6 g, 18 mmol)in THF (35 mL) was added dropwise under argon. After the addition, thecooling bath was removed and stirred at rt overnight. The reactionmixture was concentrated at reduced pressure and purified by ISCO (120g) chromatography using 15 to 30% EtOAc in hexane to provide4-[4-(3-ethoxycarbonyl-propionyl)-2,6-difluoro-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester (3.21 g, 49% yield).

Step 2

4-[2,6-Difluoro-4-(6-oxo-1,4,5,6-tetrahydro-pyridazin-3-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester

A mixture of4-[4-(3-ethoxycarbonyl-propionyl)-2,6-difluoro-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester (3.21 g, 7.27 mmol) and hydrazine monohydrate (0.7mL, 14.1 mmol) in isopropanol (20 mL) was stirred at reflux overnight.Isopropanol was concentrated at reduced pressure and partitioned betweensaturated aqueous sodium bicarbonate solution and methylene chloride.The aqueous layer was extracted twice with methylene chloride and thecombined organics was washed with brine, dried (Na₂SO₄), filtered, andconcentrated to provide a crude material. The crude material waspurified by ISCO (80 g silica gel column) chromatography using 15 to 60%EtOAc in hexane to obtain4-[2,6-difluoro-4-(6-oxo-1,4,5,6-tetrahydro-pyridazin-3-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester (0.42 g, 14%).

Step 3

6-[3,5-Difluoro-4-(piperidin-4-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one

A solution of4-[2,6-difluoro-4-(6-oxo-1,4,5,6-tetrahydro-pyridazin-3-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester (0.42 g, 1 mmol) in methylene chloride (5 mL) wastreated with trifluoro acetic acid (10 mL). The mixture was stirred atRT for 3 h and TFA was concentrated at reduced pressure to give6-[3,5-difluoro-4-(piperidin-4-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one(0.35 g, quantitative yield), MS m/z 310 (M+H).

Step 4

6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-3,5-difluoro-phenyl]-4,5-dihydro-2H-pyridazin-3-one

A solution of6-[3,5-difluoro-4-(piperidin-4-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one(350 mg, 1.1 mmol) in a mixture of DMF (2 mL) and MeOH (9 mL) wasstirred under argon. Cyclobutanone (0.38 mL, 5 mmol), sodiumcyanoborohydride (0.53 g, 8.45 mmol) and acetic acid (0.4 mL, 7 mmol)were added sequentially and stirred at 60° C. for 3 h. The reactionmixture was concentrated at reduced pressure and partitioned betweenaqueous 1M sodium carbonate solution and methylene chloride. The aqueouslayer was extracted twice with methylene chloride and the combinedorganics was washed with brine, dried (Na₂SO₄), filtered andconcentrated to provide a crude product. The crude product was purifiedby ISCO (40 g) chromatography using 2 to 5% methanol in methylenechloride to 10% methanol containing 0.2% ammonium hydroxide in methylenechloride. The recovered product was dissolved in methylene chloride andwashed with saturated aqueous sodium bicarbonate solution, brine, dried(Na₂SO₄), filtered, and concentrated to furnish a pure product. The pureproduct was crystallized with a mixture of methylene chloride, ethanol,ether and hexane to obtain6-[4-(1-cyclobutyl-piperidin-4-yloxy)-3,5-difluoro-phenyl]-4,5-dihydro-2H-pyridazin-3-one(110 mg, yield), mp 162-164° C.; MS m/z 364 (M+H)

Example 188

6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-3,5-difluoro-phenyl]-2H-pyridazin-3-one

A mixture of6-[4-(1-cyclobutyl-piperidin-4-yloxy)-3,5-difluoro-phenyl]-4,5-dihydro-2H-pyridazin-3-one(137 mg, 0.37 mmol) and cesium carbonate (232 mg, 0.71 mmol) in dimethylsulfoxide (5 mL) was heated at 130° C. 45 min. The mixture was cooled tort and partitioned between water and methylene chloride. The aqueouslayer was extracted twice with methylene chloride and the combinedorganics was washed with brine, dried (Na₂SO₄), filtered, andconcentrated to provide a crude product. The crude product was purifiedby ISCO (40 g silica gel column) chromatography using 2% to 8% methanolin methylene chloride to 10% methanol containing 0.2% ammonium hydroxidein methylene chloride. The recovered product was dissolved in methylenechloride and washed with saturated aqueous sodium bicarbonate solution,brine, dried (Na₂SO₄), filtered, and concentrated. The product wascrystallized using a mixture of ethanol, ethyl acetate, ether and hexaneto give6-[4-(1-cyclobutyl-piperidin-4-yloxy)-3,5-difluoro-phenyl]-2H-pyridazin-3-one(40 mg, 29%); Mp 195-197° C.; MS m/z 362 (M+H).

Example 189

6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-5-methyl-4,5-dihydro-2H-pyridazin-3-oneStep 1

4-(4-Propionyl-phenoxy)-piperidine-1-carboxylic acid tert-butyl ester

A solution of triphenylphosphine (22.4 g, 85.2 mmol) and 40% w/w DEAD intoluene (12.6 mL, 79.9 mmol) in tetrahydrofuran (100 mL) was cooled to0° C. A mixture of p-propiophenol (8 g, 53.3 mmol) and4-hydroxypiperidine-1-carboxylic acid tert-butyl ester (12.9 g, 63.9mmol) in THF (75 mL) was added dropwise at 0° C. After the addition, thecooling bath was removed and stirred at rt overnight. The reactionmixture was concentrated at reduced pressure and purified by ISCO (120 gsilica gel column) chromatography using 5 to 30% EtOAc in hexane toprovide an impure product (12 g). The product was again treated withtriphenylphosphine and 40% w/w DEAD in toluene, after the completion,the reaction was concentrated at reduced pressure. The crude residue wastriturated with a mixture of methylene chloride and hexane and filteredand the filtrate was concentrated at reduced pressure and purified byISCO (120 g silica gel column) chromatography using 5 to 30% EtOAc inhexane to provide 4-(4-propionylphenoxy)-piperidine-1-carboxylic acidtert-butyl ester (10 g, 56%).

Step 2

4-[4-(3-Ethoxycarbonyl-2-methyl-propionyl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester

A solution of 4-(4-propionyl-phenoxy)-piperidine-1-carboxylic acid ethylester (5 g, 15 mmol) in tetrahydrofuran (40 mL) was cooled to 0° C.Lithium diisopropylamide, (2M solution in THF) (8 mL, 16.4 mmol) wasadded dropwise and warmed to rt for 30 min. The reaction was cooledagain to 0° C. and ethyl bromoacetate (1.8 mL, 16 mmol) was addeddropwise and warmed to rt for 30 min and then quenched with aqueous 1MHCl acid at 0° C. The aqueous layer was extracted twice with methylenechloride and the combined organics were washed with brine, dried(Na₂SO₄), filtered, and concentrated to give4-[4-(3-ethoxycarbonyl-2-methyl-propionyl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester (5.8 g, 92%), MS m/z 364 (M−55).

Step 3

4-[4-(4-Methyl-6-oxo-1,4,5,6-tetrahydro-pyridazin-3-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester

A mixture of crude4-[4-(3-ethoxycarbonyl-2-methyl-propionyl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester (9 g, 21.4 mmol) and hydrazine monohydrate (3.58ml, 71.6 mmol) in isopropanol (70 mL) was heated at 90° C. for 2 daysand concentrated at reduced pressure to give a crude residue. The crudereside was dissolved in methylene chloride and washed with saturatedaqueous sodium bicarbonate solution, brine, dried (Na₂SO₄), filtered,and concentrated to give a crude product. The crude product was purifiedby ISCO (120 g silica gel column) chromatography using 2 to 5% methanolin methylene chloride to obtain4-[4-(4-methyl-6-oxo-1,4,5,6-tetrahydro-pyridazin-3-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester (4.4 g, 53%), MS m/z 388 (M+H)

Step 4

5-Methyl-6-[4-(piperidin-4-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one

A solution of4-[4-(4-methyl-6-oxo-1,4,5,6-tetrahydro-pyridazin-3-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester (1 g, 2.5 mmol) in methylene chloride at RT wastreated with trifluoroacetic acid (3 mL, 38.9 mmol) and stirred at RTfor 3 h. TFA was evaporated at reduced pressure to obtain5-methyl-6-[4-(piperidin-4-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one(0.35 g, 47%), MS m/z 288 (M+H).

Step 5

6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-5-methyl-4,5-dihydro-2H-pyridazin-3-one

A solution of5-methyl-6-[4-(piperidin-4-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one(3.2 mg, 11 mmol) in a mixture of DMF (4 mL) and MeOH (20 mL) wasstirred under argon. Cyclobutanone (4.2 mL, 56 mmol), sodiumcyanoborohydride (7 g, 111 mmol) and acetic acid (1.5 mL, 26 mmol) wereadded sequentially and stirred at 60° C. for 20 h. The reaction mixturewas concentrated at reduced pressure then quenched with 1M sodiumcarbonate solution at 0° C. and extracted twice with methylene chlorideto provide a crude product. The crude product was purified by ISCO (40 gsilica gel column) chromatography using 2 to 5% methanol in methylenechloride to 10% methanol containing 0.2% ammonium hydroxide in methylenechloride. The recovered product was dissolved in methylene chloride andwashed with saturated aqueous sodium bicarbonate solution, brine, dried(Na₂SO₄), filtered, and concentrated to furnish a pure product. The pureproduct was crystallized using from a mixture of EtOAc, ethanol, etherand hexane to obtain6-[4-(1-cyclobutyl-piperidin-4-yloxy)-3,5-difluoro-phenyl]-4,5-dihydro-2H-pyridazin-3-one(640 mg, 17%), mp 163-165° C.; MS m/z 342 (M+H).

Example 190

(R)-6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-5-methyl-4,5-dihydro-2H-pyridazin-3-oneExample 191

(S)-6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-5-methyl-4,5-dihydro-2H-pyridazin-3-one

Racemic Example 189 (660 mg) was separated into two enantiomers bychiral chromatography using chiralPak and 0.1% diethylamine in methanol.

Example 190:R(−)-6-[4-(cyclobutyl-piperidin-4-yloxy)-phenyl-5-methyl-4,5-dihydro-2H-pyridazin-3-onemp 188-190° C., MS m/z 342 (M+H), Hg 365=−29.2, Conc. ˜0.1 g/mL

Example 191:S(+)-6-[4-(cyclobutyl-piperidin-4-yloxy)-phenyl-5-methyl-4,5-dihydro-2H-pyridazin-3-oneone mp 188-190° C., MS m/z 342 (M+H), Hg 365=+30.5, Conc. ˜0.1 g/mL).

Example 192

Example 192 was synthesized from 1-(4-methoxyphenyl)butan-1-one usingprocedures for example 189; Mp 152-154° C.; MS m/z 356 (M+H).

Example 193

6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-5-methyl-2-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one Step 1

4-[4-(3-Carboxy-2-methyl-propionyl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester

A mixture of4-[4-(3-ethoxycarbonyl-2-methyl-propionyl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester (Example 189 step 2) (5.7 g, 14 mmol) and 1N NaOH(18 mL) in methanol was heated at 65° C. for 1 h. Methanol wasevaporated at reduced pressure and diluted with water then cooled to 0°C. The aqueous layer was neutralized carefully with citric acid andextracted twice with methylene chloride to obtain a crude4-[4-(3-carboxy-2-methyl-propionyl)phenoxy]-piperidine-1-carboxylic acidtert-butyl ester (4.3 g, 81%), MS m/z 390 (M−1)

Step 2

4-[4-(4-Methyl-6-oxo-1-pyridin-2-yl-1,4,5,6-tetrahydro-pyridazin-3-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester

A mixture of4-[4-(3-carboxy-2-methyl-propionyl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester (4.3 g, 11 mmol) and 2-hydrazinopyridine (1.5 g,14 mmol) in isopropanol (45 mL) was heated in a microwave reactor (300Watts) at 160° C. for 150 min. Isopropanol was evaporated at reducedpressure and triturated with ether (150 mL) to obtain an orange solid (3g). The filtrate was concentrated and purified by ISCO (80 g silica gelcolumn) chromatography using 1.5 to 3.5% methanol in methylene chlorideto obtain4-[4-(4-methyl-6-oxo-1-pyridin-2-yl-1,4,5,6-tetrahydropyridazin-3-yl)phenoxy]-piperidine-1-carboxylicacid tert-butyl ester (0.3 g), mp 164-166° C., MS m/z 465 (M+H).

Example 193 was synthesized using the product from step 2 and methodsdescribed for example 189 step 4 and step 5.

Example Structure Mp (° C.) MS m/z 193

143-5 HCl 419 (M + H) 6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-5-methyl-2-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one

Example 194

5-Methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-oneStep 1

4-(4-Methoxy-phenyl)-3-methyl-4-oxo-butyric acid ethyl ester

A solution of 4-methoxypropiophenone (24 g, 140 mmol) in tetrahydrofuran(220 mL) was cooled to 0° C. Lithium diisopropylamide, (2M solution inTHF) (126 mL, 248 mmol) was added dropwise and warmed to rt for 30 min.The reaction was cooled again to 0° C. and ethyl bromoacetate (18 mL,161 mmol) was added dropwise and warmed to rt for 30 min and thenquenched with aqueous 1M HCl acid at 0° C. The aqueous layer wasextracted twice with methylene chloride and the combined organics werewashed with brine, dried (Na₂SO₄), filtered, and concentrated to give4-(4-methoxyphenyl)-3-methyl-4-oxobutyric acid ethyl ester (44 g), MSm/z 205 (M−45)

Step 2

4-(4-Hydroxy-phenyl)-3-methyl-4-oxo-butyric acid ethyl ester

A mixture of crude 4-(4-methoxy-phenyl)-3-methyl-4-oxo-butyric acidethyl ester (44 g, 175.8 mmol), acetic acid (300 mL) and 48% aqueous HBr(150 mL) was stirred at reflux for 10 h. The reaction was cooled to rt,concentrated at reduced pressure then partitioned between methylenechloride and water and the aqueous layer was extracted three times withmethylene chloride and concentrated to provide a crude material. Thecrude material was dissolved in ethanol (125 mL) and added amberlystthen heated at 85° C. for 15 h. The reaction mixture was filtered overcelite at rt and the filtrate was concentrated at reduced pressure andthen partitioned between water and methylene chloride. The aqueous layerwas extracted twice with methylene chloride to furnish a crude productand the crude product was purified by ISCO (330 g silica gel column)chromatography using 20 to 30% EtOAc in hexane to obtain a mixture (19g) of 4-(4-hydroxyphenyl)-3-methyl-4-oxo-butyric acid ethyl ester (MSm/z 235 (M−H) and p-hydroxypropiophenone. The mixture was used for thenext reaction without further purification.

Step 3

4-[4-(3-Chloro-propoxy)-phenyl]-3-methyl-4-oxo-butyric acid ethyl ester

A mixture of 4-(4-hydroxyphenyl)-3-methyl-4-oxo-butyric acid ethyl ester(12.5 g, 52.9 mmol), 1-bromo-3-chloropropane (11.3 mL, 114.6 mmol) andK₂CO₃ (21.9 g, 159 mmol) in acetone (200 mL) was stirred at 60° C. for15 h. The reaction was cooled to RT and filtered over celite and thefiltrate was evaporated at reduced pressure to give a crude residue. Thecrude residue was partitioned between methylene chloride and saturatedaqueous sodium bicarbonate solution and the aqueous layer was extractedtwice with methylene chloride. The combined organics was washed withbrine, dried (Na₂SO₄), filtered, and concentrated to provide a crudeproduct. The crude product was purified by ISCO (330 g) chromatographyusing 15% EtOAc in hexane to produce4-[4-(3-chloro-propoxy)-phenyl]-3-methyl-4-oxo-butyric acid ethyl ester(9.7 g, 56%), MS m/z 267 (M−45)

Step 4

3-Methyl-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4-oxo-butyricacid ethyl ester

A mixture of 4-[4-(3-chloro-propoxy)-phenyl]-3-methyl-4-oxo-butyric acidethyl ester (7 g, 22 mmol), K₂CO₃ (9.3 g, 67 mmol), NaI (330 mg, 2.2mmol), and (R)-methyl-pyrrolidinium benzenesulfonate (11 g, 47 mmol) inCH₃CN (160 mL) was heated under argon at 80° C. for 36 h. The reactionmixture was concentrated at reduced pressure and partitioned betweensaturated aqueous sodium bicarbonate solution and methylene chloride.The aqueous layer was extracted twice with methylene chloride and thecombined organics was washed with brine, dried (Na₂SO₄), filtered, andconcentrated to provide a crude material. The crude material waspurified by ISCO (80 g silica gel column) chromatography using 2% to 9%methanol in methylene chloride to 10% methanol containing 2.5 mLammonium hydroxide in methylene chloride to afford a pure product. Thepure product was dissolved in methylene chloride and washed withsaturated aqueous sodium bicarbonate solution, brine, dried (Na₂SO₄),filtered, and concentrated to give3-methyl-4-{4-R-2methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4-oxo-butyricacid ethyl ester (8.39 g, quantitative yield), MS m/z 362 (M+H).

Step 5

5-Methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one

A mixture of3-methyl-4-{4-R-2methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4-oxo-butyricacid ethyl ester (8.39 g, 23.2 mmol) and hydrazine monohydrate (5 mL,100 mmol) in isopropanol was heated at 100° C. for 36 h. Isopropanol wasevaporated at reduced pressure and quenched with saturated aqueoussodium bicarbonate solution and extracted twice with methylene chloride.The combined organics was washed with brine, dried (Na₂SO₄), filtered,and concentrated to afford a crude product. The crude product waspurified by ISCO (80 g) chromatography using 2 to 10% methanol inmethylene chloride to 10% methanol containing 4 mL ammonium hydroxide inmethylene chloride to afford a pure product. The pure product wasdissolved in methylene chloride and washed with saturated aqueous sodiumbicarbonate solution, brine, dried (Na₂SO₄), filtered, and concentratedto give5-methyl-6-{4-[3-R-2-methyl-pyrrolidin-1-yl)propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one(6.1 g, 80%, >95% purity). The product was dissolved in a mixture ofethanol and ethyl acetate and 1M HCl (18 mL) in ether was added and themixture was concentrated at reduced pressure. Fresh ethanol and ethylacetate were added and concentrated under vacuum and again dissolved inethanol and slowly added ethyl acetate, ether and hexane. After stirringfor 15 min at RT solid separated, and the solid was filtered, washedwith ether and dried at 85° C. in a ChemDry for 15 h to provide example194 HCl as an off-white solid (5.8 g), mp 169-171° C., MS m/z 330 (M+H).

Example 195

5-Methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-oneExample 196

5-Methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one

Racemic example 194 (5.8 g) of was separated into two diastereomersusing chiralCel and 0.1% diethylamine in methanol.

Example 195:5-methyl-6-[4-[3-(R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-oneHCl (2.4 g), mp 149-151° C., MS m/z 367 (M+H).

Example 196:5-methyl-6-[4-[3-(R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-oneHCl (2.6 g), mp 189-191° C., MS m/z 367 (M+H)

Example 197 (racemic) and example 198 (racemic) were synthesized as HClsalts using methods described for example 194.

Example Structure mp (° C.) MS m/z 197

223-225 HCl 330 (M + H) 5-Methyl-6-[4-(3-piperidin-1-yl-propoxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one 198

161-163 HCl 316 (M + H) 5-Methyl-6-[4-(3-pyrrolidin-1-yl-propoxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one

Example 199

6-{(R)-2-Methyl-4-[3-(2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-oneStep 1

4-(4-Hydroxy-2-methyl-phenyl)-4-oxo-butyric acid ethyl ester

A mixture of 4-(4-methoxy-2-methyl-phenyl)-4-oxo-butyric acid (2 g, 9mmol), acetic acid (30 mL) and 48% aqueous HBr (10 mL) was heated at130° C. for 5.5 h. The reaction was cooled to rt and concentrated atreduced pressure and azeotrope twice with benzene to give a cruderesidue. The crude residue was dissolved in ethanol (25 mL) and addedamberlyst then heated at 90° C. for 18 h. The reaction was filtered overcelite and evaporated ethanol at reduced pressure then quenched withwater and extracted twice with methylene chloride to obtain4-(4-hydroxy-2-methyl-phenyl)-4-oxo-butyric acid ethyl ester (1.6 g,75%). The crude material was used for the next reaction withoutpurification.

Step 2

4-[4-(3-Chloro-propoxy)-2-methyl-phenyl]-4-oxo-butyric acid ethyl ester

4-[4-(3-chloro-propoxy)-2-methyl-phenyl]-4-oxo-butyric acid ethyl esterwas prepared from 4-(4-hydroxy-2-methyl-phenyl)-4-oxo-butyric acid ethylester according to the procedure in step 3 example 184 MS m/z 267(M−45).

Step 3

4-{2-Methyl-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4-oxo-butyricacid ethyl ester

4-{2-methyl-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4-oxo-butyricacid ethyl ester (0.28 g, 67%) was prepared from4-[4-(3-chloro-propoxy)-2-methyl-phenyl]-4-oxo-butyric acid ethyl ester(0.36 g, 1.15 mmol) according to the procedure in step 4 of example 184;MS m/z 362 (M+H).

Step 4

6-{(R)-2-Methyl-4-[3-(2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one

6-{(R)-2-methyl-4-[3-(2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-onewas prepared from 4-[4-(3-chloro-propoxy)-2-methyl-phenyl]-4-oxo-butyricacid ethyl ester (0.28 g, 0.77 mmol) according to the procedure in step5 of example 184 HCl; Mp 121-123° C.; MS m/z=330 (M+H).

Examples 200-204 were synthesized using Cu(0) coupling methods accordingto Example 21 or CuI/dioxane/1,2-diaminocyclohexane/Cs₂CO₃ and startingwith R-1-[3-(4-bromo-phenoxy)propyl]-2-methyl-pyrrolidine or4-(5-bromopyridin-2-yloxy)-piperidine-1-carboxylic acid tert-butylester.

Example Structure Mp (° C.) MS m/z 200

86-9  390 (M + H) 2-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-6-phenyl-2H-pyridazin-3-one 201

168-70  fumarate 328 (M + H)6-Methyl-2-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 202

70-3  364 (M + H) 2-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-phthalazin-1-one 203

155-9  fumarate 403 (M + H)2-[6-(1-Cyclobutyl-piperidin-4-yloxy)-pyridin-3-yl]-6-phenyl-2H-pyridazin-3-one 204

87-90 391 (M + H) 2-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-6-pyridin-3-yl-2H-pyridazin-3-one 262

51-55 fumarate 354 (M + 1)6-Cyclopropyl-2-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one

Example 205

4-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-3-methyl-6H-isoxazolo[3,4-d]pyridazin-7-oneStep 1

1-(4-Methoxy-phenyl)-butane-1,3-dione

To 9.80 mL of ethyl acetate (100 mmol) in 40 mL dry THF at roomtemperature was added 2.0 g of 60% sodium hydride (49.9 mmol), 7.50 g of4′-methoxyacetophenone (49.9 mmol), 100.0 mg of 18-crown-6 (0.40 mmol),and 2 drops of ethanol. After 30 minutes, the reaction was refluxed for1 h, and then 100 mL of dry THF was added. After an additional 1 h, 30mL THF was added. After 1 h the reaction was cooled to 0° C. and 25 mLof 10% aqueous sulfuric acid was added. The product was extracted withdiethyl ether. The ether extracts were dried with Na₂SO₄, filtered, andconcentrated in vacuo. The crude material was purified via silica gelchromatography eluting with 4:1 hexane:ethyl acetate to give 5.8 g of1-(4-methoxyphenyl)butane-1,3-dione containing 30% starting material(via ¹H NMR 42% yield).

Step 2

4-(4-Methoxy-benzoyl)-5-methyl-isoxazole-3-carboxylic acid ethyl ester

To 7.04 mL of 21% sodium ethoxide in ethanol (18.8 mmol) in 60 mLethanol at 0° C. was added 4.70 g of 1-(4-methoxyphenyl)butane-1,3-dione(17.1 mmol) in 60 mL ethanol dropwise over 24 minutes. After 30 min asolution of 2.59 g of ethyl chloro-(hydroximino)acetate (17.1 mmol) in30 mL ethanol was added dropwise over 6 minutes. The reaction was warmedto room temperature slowly. When TLC indicated the reaction wascomplete, the reaction was concentrated in vacuo. Water and saturatedNaHCO₃ was added and the product extracted with ethyl acetate. The ethylacetate extracts were dried with Na₂SO₄, filtered, and concentrated invacuo. The crude material was purified via silica gel chromatographyeluting with 8:1 hexane:ethyl acetate to give4-(4-methoxybenzoyl)-5-methylisoxazole-3-carboxylic acid ethyl esterwhich was dried overnight under high vacuum to give 3.74 g (71.8%).

Step 3

4-(4-Methoxyphenyl)-3-methyl-6H-isoxazolo[3,4-d]pyridazin-7-one

A solution of 2.47 g of4-(4-methoxybenzoyl)-5-methylisoxazole-3-carboxylic acid ethyl ester(8.54 mmol) and 0.598 mL of hydrazine monohydrate (12.0 mmol) in 18.4 mLethanol was stirred at room temperature for 19 hours. The heterogeneousreaction was cooled in an ice bath then filtered off the white solid,washing with cold ethanol then diethyl ether. Dried on under high vacuumto give 2.06 g (92%) of4-(4-methoxyphenyl)-3-methyl-6h-isoxazolo[3,4-d]pyridazin-7-one.

Step 4

4-(4-Hydroxy-phenyl)-3-methyl-6H-isoxazolo[3,4-d]pyridazin-7-one

To 1.05 g of4-(4-methoxyphenyl)-3-methyl-6h-isoxazolo[3,4-d]pyridazin-7-one (4.08mmol) in 15 mL dry DMF was added 1.03 g of sodium ethanethiolate in 15mL dry DMF at room temperature. The reaction was then heated at 100° C.for 2.5 h. Added water and 1M HCl until acidic. Extracted the productwith diethyl ether and dried the extracts with Na₂SO₄, filtered, andconcentrated in vacuo. The product was purified via silica gelchromatography eluting with 95:5 dichloromethane:methanol to give 533 mgof 4-(4-hydroxyphenyl)-3-methyl-6h-isoxazolo[3,4-d]pyridazin-7-one; Mp268-276° C.; MS m/z 216 (M-N₂+H).

Step 5

4-[4-(3-Methyl-7-oxo-6,7-dihydro-isoxazolo[3,4-d]pyridazin-4-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester

To a solution of 805 mg of triphenylphosphine (3.07 mmol) in 10 mL dryTHF at 0° C. was added 1.30 mL 40% w/w diethylazodicarboxylate intoluene (8.26 mmol). After 15 min, a solution of 524 mg of4-(4-hydroxyphenyl)-3-methyl-6h-isoxazolo[3,4-d]pyridazin-7-one (2.05mmol) and 494 mg of 4-hydroxypiperidine-1-carboxylic acid tert-butylester (2.46 mmol) in 18 mL dry THF were added dropwise. The reaction wasslowly warmed to room temperature. After 14 h water was added and theproduct was extracted with ethyl acetate. The extracts were dried withNa₂SO₄, filtered, and concentrated in vacuo. The product was purifiedvia silica gel chromatography eluting with 1:1 hexane:ethyl acetate togive 985 mg of4-[4-(3-methyl-7-oxo-6,7-dihydroisoxazole[3,4-d]pyridazin-4-yl)phenoxy]piperidine-1-carboxylicacid tert-butyl ester 65.4%.

Step 6 Example 206

3-Methyl-4-[4-(piperidin-4-yloxy)-phenyl]-6H-isoxazolo[3,4-d]pyridazin-7-one

To 980 mg of4-[4-(3-methyl-7-oxo-6,7-dihydroisoxazole[3,4-d]pyridazin-4-yl)phenoxy]-piperidine-1-carboxylicacid tert-butyl ester (1.3 mmol) in 20 mL of dichloromethane was added1.0 mL of trifluoroacetic acid (13 mmol). After stirring at roomtemperature for 3 hours, an additional 0.5 mL of trifluoroacetic acidwas added. The reaction was concentrated in vacuo as monitored by TLCand concentrated and triturated with diethyl ether to give 375 mg (98%pure) (63% yield) of example 206 as an off-white solid3-methyl-4-[4-(piperidin-4-yloxy)phenyl]-6h-isoxazolo-[3,4-d]pyridazin-7-oneTFA salt. Mp 283-239° C.; MS m/z 299 (M-N₂+H).

Step 7 Example 205

4-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-3-methyl-6H-isoxazolo[3,4-d]pyridazin-7-one

To 369 mg of example 206(3-methyl-4-[4-(piperidin-4-yloxy)phenyl]-6h-isoxazolo-[3,4-d]pyridazin-7-onetrifluoroacetic acid salt) (0.838 mmol) and 84 μL acetic acid (1.5 mmol)in 6 mL dry methanol and 2 mL dry DMF at 0° C. was added 260 mg ofsodium cyanoborohydride (4.2 mmol) and then 190 μL of cyclobutanone (2.5mmol). The reaction was heated at 60° C. After 1 h, the reaction wascomplete as determined by LC/MS and was concentrated in vacuo. Water and2M Na₂CO₃ was added and the product was extracted with dichloromethane.The extracts were dried with Na₂SO₄, filtered, and concentrated invacuo. The crude product was purified via silica gel chromatographyeluting with 500:15:10 dichloromethane:methanol:7N ammonia in methanolto give a colorless oil which was re-concentrated in vacuo with diethylether. Added diethyl ether and upon standing, a white solid formed whichwas triturated with ether to yield 56 mg (17%) of example 205 Mp182.5-184.0° C.; MS m/z 353 (M-N₂+H).

Example 207

3-Methyl-4-[4-(3-piperidin-1-yl-propoxy)-phenyl]-6H-isoxazolo[3,4-d]pyridazin-7-oneStep 1

A mixture of 5.97 g of 4′-hydroxyacetophenone (43.8 mmol), 13.0 g of1-(3-chloropropyl)-piperidine hydrochloride (65.8 mmol), 12.70 g ofpotassium carbonate (91.89 mmol), and 3.28 g of sodium iodide (21.9mmol) in 100 mL dry acetone was stirred at reflux. After 1.5 h, thereaction was cooled to room temperature, filtered and concentrated.Ethyl acetate was added and the white solid that remained was filteredoff. The filtrate was concentrated in vacuo and the crude residue waspurified via silica gel chromatography using a gradient of ethyl acetatethen 400:20:10 ethyl acetate:7N ammonia in methanol:methanol to yield583 mg of 1-[4-(3-piperidin-1-ylpropoxy)phenyl]ethanone as an oil. MSm/z 265 (M+H).

Step 2

1-[4-(3-Piperidin-1-yl-propoxy)-phenyl]-butane-1,3-dione

To 430 μL of ethyl acetate (4.4 mmol) in 10 mL dry THF at roomtemperature was added 180 mg of 60% sodium hydride (4.4 mmol), 15.0 mgof 18-crown-6 (0.0568 mmol), 2 drops of ethanol, and then 578 mg (2.212mmol) of 1-[4-(3-piperidin-1-ylpropoxy)phenyl]ethanone in 10 mL dry THF.After 30 min, the reaction was refluxed. An additional 18 mL of dry THFwas added after 1.5 hours to reduce the viscosity of the reaction. Afteran additional 2 hours, 0.50 mL of 12.1 M aq. HCl was added to thereaction and the reaction was concentrated in vacuo. Water and saturatedNaHCO₃ was added and the product extracted with ethyl acetate. The ethylacetate extracts were dried with Na₂SO₄, filtered, and concentrated invacuo. The crude material was purified via silica gel chromatographyeluting with 500:20:12 dichloromethane:methanol:7N ammonia in methanolto give a yellow oil which solidified to give 450 mg (66%) of1-[4-(3-piperidin-1-ylpropoxy)-phenyl]butane-1,3-dione as a yellowsolid; Mp 43.0-45.5° C.; MS m/z 304 (M+H).

Step 3

5-Methyl-4-[4-(3-piperidin-1-yl-propoxy)-benzoyl]-isoxazole-3-carboxylicacid ethyl ester

To 597 μL of 21% sodium ethoxide in ethanol (1.595 mmol) in 4 mL ethanolat 0° C. was added 440 mg of1-[4-(3-piperidin-1-ylpropoxy)phenyl]butane-1,3-dione (1.45 mmol) in 5.5mL ethanol dropwise. After 30 min, a solution of 220 mg of ethylchloro(hydroximino)acetate (1.45 mmol) in 3 mL ethanol was addeddropwise. The reaction was warmed to room temperature slowly. After 19.5h the reaction was concentrated in vacuo. Water and saturated NaHCO₃ wasadded and the product extracted with ethyl acetate. The ethyl acetateextracts were dried with Na₂SO₄, filtered, and concentrated in vacuo.The crude material was purified via silica gel chromatography elutingwith 500:15:10 dichloromethane:methanol:7N ammonia in methanol to give300 mg (50%) of a gold oil determined to be5-methyl-4-[4-(3-piperidin-1-ylpropoxy)benzoyl]-isoxazole-3-carboxylicacid ethyl ester; MS m/z 401 (M+H).

Step 4 Example 207

3-Methyl-4-[4-(3-piperidin-1-yl-propoxy)-phenyl]-6H-isoxazolo[3,4-d]pyridazin-7-one

To 291.3 mg of 5-methyl-4-[4-(3-piperidin-1-ylpropoxy)benzoyl]isoxazole-3-carboxylic acid ethyl ester (0.7057 mmol) in 1.54 mL ofethanol at room temperature was added 49.4 μL of hydrazine monohydrate(0.988 mmol). After 21 h, the heterogeneous reaction was cooled to 0° C.and filtered. The white solid was washed with cold ethanol then diethylether and dried at 65° C. under high vacuum. Yield 120 mg (46%) of awhite solid Mp 178-9; MS m/z 369 (M+H).

Example 208

3-Methyl-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-6H-isoxazolo[3,4-d]pyridazin-7-one

Example 208 was prepared using methods described for example 207; Mp169-70° C.; MS m/z 369 (M+H).

Example 178 Method B Step 1

4-(4-Hydroxy-phenyl)-4-oxo-butyric acid ethyl ester

In a 1 L round bottom flask, 4-(4-methoxyphenyl)-4-oxo-butyric acid (25g, 106 mmol) in 48% HBr (125 mL) and acetic acid (250 mL) was heated toreflux 18 h. The reaction was cooled slightly and ethanol (250 mL) wasadded. The solvent was concentrated under vacuum. Additional ethanol(100 mL) was added and solvent concentrated under vacuum again. Theresulting oil was crystallized from ethyl acetate/hexanes to produce8.65 g (37%). MS m/z=223 (M+H).

Step 2

4-[4-(3-Chloro-propoxy)-phenyl]-4-oxo-butyric acid ethyl ester

In a 1 L round bottom flask, 4-(4-hydroxyphenyl)-4-oxo-butyric acidethyl ester (8.65 g, 39.0 mmol), 1-bromo-3-chloro-propane (6.1 g, 61.0mmol), and potassium carbonate (9.3 g, 67.1 mmol) in acetonitrile (300mL) was heated to reflux 14 h. The reaction was cooled and the solventconcentrated under vacuum. The slurry was partitioned between methylenechloride and water, separated and dried over MgSO₄. Purification withsilica gel chromatography eluting with hexanes/ethyl acetate (3:1)produced 7.9 g (68%). MS m/z 299 (M+H).

Step 3

6-[4-(3-Chloro-propoxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one

In a 500 mL round bottom flask,4-[4-(3-chloro-propoxy)-phenyl]-4-oxo-butyric acid ethyl ester (7.85 g,26.3 mmol), and hydrazine monohydrate (2.55 mL, 52.7 mmol), inisopropanol (200 mL) was heated to reflux 14 h. The reaction was cooledand the solvent concentrated under vacuum. Purification with silica gelchromatography eluting with methylene chloride/methanol (95:5) produced5.2 g (74%). MS m/z 267 (M+H).

Example 178 Step 4

6-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4,5-dihydro-2H-pyridazin-3-one

In a 500 mL round bottom flask,6-[4-(3-chloro-propoxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one (5.2 g,19.5 mmol), benzenesulfonate (R)-2-methyl-pyrrolidinium (9.5 g, 39.0mmol), potassium carbonate (10.8 g, 78.0 mmol), and potassium iodide(200 mg, 1.2 mmol) in acetonitrile (300 mL) was heated to reflux 14 h.The reaction was cooled and the solvent concentrated under vacuum. Theslurry was partitioned between methylene chloride and water, then washedwith water three times. The organics were extracted three times with 3%citric acid solution. The combined aqueous layers were basified withsat. NaHCO₃ sol. and extracted with methylene chloride, then dried overMgSO₄. Ethereal HCl was added and the solvents reduced under vacuum.Crystallization from MeOH/Et₂O produced 3.17 g (46%). Mp 221-223° C. MSm/z 316 (M+H).

Example 209 Step 1

6-(3-Chloro-propoxy)-3,4-dihydro-2H-naphthalen-1-one

In a 500 mL round bottom flask,6-hydroxy-3,4-dihydro-2H-naphthalen-1-one (10 g, 61.0 mmol),1-bromo-3-chloro-propane (9.6 g, 61.0 mmol), and potassium carbonate(9.3 g, 67.1 mmol) in acetonitrile (300 mL) was heated to reflux 14 h.The reaction was cooled and the solvent concentrated under vacuum. Theslurry was partitioned between methylene chloride and water, separated,dried over MgSO₄. Purification with silica gel chromatography elutingwith hexanes/ethyl acetate (3:1) produced 10.6 g (73%). Mp 85-87° C. MSm/z 239 (M+H).

Step 2

8-(3-Chloro-propoxy)-5,6-dihydro-2H-benzo[h]cinnolin-3-one

In a 100 mL round bottom flask,6-(3-chloro-propoxy)-3,4-dihydro-2H-naphthalen-1-one (1 g, 4.2 mmol),and glyoxylic acid monohydrate (387 mg, 4.2 mmol), in acetic acid (10mL) was heated to reflux 6 h. The reaction was cooled and hydrazinemonohydrate (0.41 mL, 8.4 mmol) was added and the reaction was heated toreflux 14 h. The reaction was cooled and the solvent concentrated undervacuum. The slurry was partitioned between methylene chloride and water,separated, dried over MgSO₄. Purification with silica gel chromatographyeluting with methylene chloride/methanol (95:5) produced 620 mg (51%).MS m/z 291 (M+H).

Example 209 Step 3

8-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-5,6-dihydro-2H-benzo[h]cinnolin-3-one

In a 100 mL round bottom flask,8-(3-chloro-propoxy)-5,6-dihydro-2H-benzo[h]cinnolin-3-one (600 mg, 2.1mmol), benzenesulfonate (R)-2-methyl-pyrrolidinium (1.02 g, 4.2 mmol),potassium carbonate (1.14 g, 8.3 mmol), and potassium iodide (10 mg,0.06 mmol) in acetonitrile (60 mL) was heated to reflux 14 h. Thereaction was cooled and the solvent concentrated under vacuum. Theslurry was partitioned between methylene chloride and water, and thenwashed with water three times. The organics were extracted three timeswith 3% citric acid solution. The combined aqueous layers were basifiedwith sat. NaHCO₃ sol. and extracted with methylene chloride, then driedover MgSO₄. Ethereal HCl was added and the solvents reduced undervacuum. Crystallization from MeOH/Et₂O produced 85 mg (11%). Mp 289-292°C. MS m/z 340 (M+H).

Example 210

5-Methyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one

Following the procedure of Example 209: Mp 253-255° C. MS m/z=328 (M+H).

Example 211

5-Ethyl-6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one

Following the procedure of Example 209: Mp 272-275° C. MS m/z=342 (M+H).

Example 212 Step 1

6-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-3,4-dihydro-2H-naphthalen-1-one

In a 1 L round bottom flask,6-(3-chloro-propoxy)-3,4-dihydro-2H-naphthalen-1-one (10.0 g, 41.9mmol), benzenesulfonate (R)-2-methyl-pyrrolidinium (13.15 g, 84.0 mmol),potassium carbonate (23.15 g, 168 mmol), and potassium iodide (100 mg,0.6 mmol) in acetonitrile (600 mL) was heated to reflux 14 h. Thereaction was cooled and the solvent concentrated under vacuum. Theslurry was partitioned between methylene chloride and water, then washedwith water three times. The organics were extracted three times with 3%citric acid solution. The combined aqueous layers were basified withsat. NaHCO₃ sol. and extracted with methylene chloride, then dried overMgSO₄. Ethereal HCl was added and the solvents reduced under vacuum.Crystallization from MeOH/Et₂O produced 8.75 g (65%). Mp 183-185° C. MSm/z=288 (M+H).

Example 212 Step 2

8-[3-(2-Methyl-pyrrolidin-1-yl)-propoxy]-4,4a,5,6-tetrahydro-2H-benzo[h]cinnolin-3-one

In a 250 mL round bottom flask,6-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-3,4-dihydro-2H-naphthalen-1-one(3.0 g, 9.3 mmol), and glyoxylic acid monohydrate (1.28 g, 13.9 mmol),in acetic acid (60 mL) was heated to reflux 3 h. The reaction was cooledand zinc dust (1.21 g, 18.5 mmol) was added and the reaction was heatedto reflux 14 h. The reaction was cooled and diluted with water (120 mL).The mixture was basified to pH 8 with NH₄OH and then hydrazinemonohydrate (0.93 mL, 18.5 mmol) was added. The reaction was heated toreflux 2 h. The reaction was cooled and re-basified with NaHCO₃, thenextracted with methylene chloride three times. The organics were driedover MgSO₄, then ethereal HCL was added. The solvents were removed undervacuum and the product was crystallized with MeOH/ether to produce 1.16g (33%). Mp 193-195° C. MS m/z 342 (M+H).

Example 213 Step 1

1-[4-(3-Chloro-propoxy)-2-methoxy-phenyl]-ethanone

In a 250 mL round bottom flask, 1-(4-hydroxy-2-methoxy-phenyl)ethanone(5.0 g, 30.0 mmol), 1-bromo-3-chloro-propane (3.27 mL, 33.1 mmol), andpotassium carbonate (4.75 g, 33.1 mmol) in acetonitrile (100 mL) washeated to reflux 14 h. The reaction was cooled and the solventconcentrated under vacuum. The slurry was partitioned between methylenechloride and water, separated, dried over MgSO₄. Purification withsilica gel chromatography eluting with hexanes/ethyl acetate (3:1)produced 6.18 g (85%). Mp 51-53° C. MS m/z 243 (M+H).

Step 2

1-{2-Methoxy-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-ethanone

In a 250 mL round bottom flask,1-[4-(3-chloro-propoxy)-2-methoxy-phenyl]-ethanone (6.18 g, 25.5 mmol),benzenesulfonate (R)-2-methyl-pyrrolidinium (12.4 g, 50.9 mmol),potassium carbonate (14.1 g, 102 mmol), and potassium iodide (20 mg,0.12 mmol) in acetonitrile (100 mL) was heated to reflux 14 h. Thereaction was cooled and the solvent concentrated under vacuum. Theslurry was partitioned between methylene chloride and water, then washedwith water three times. The organics were extracted three times with 3%citric acid solution. The combined aqueous layers were basified withsat. NaHCO₃ sol. and extracted with methylene chloride, then dried overMgSO₄. The solvents were removed under vacuum to produce 4.25 g (57%) ofoil. MS m/z 292 (M+H).

Example 213 Step 3

6-{2-Methoxy-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one

In a 100 mL round bottom flask,1-{2-methoxy-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-ethanone(4.24 g, 14.5 mmol), and glyoxylic acid monohydrate (2.01 g, 21.8 mmol),in acetic acid (20 mL) was heated to reflux 3 h. The reaction was cooledand diluted with water (40 mL). The mixture was basified to pH 8 withNH₄OH and then hydrazine monohydrate (1.41 mL, 29.1 mmol) was added. Thereaction was heated to reflux 2 h. The reaction was cooled andre-basified with NaHCO₃, then extracted with methylene chloride threetimes. The organics were dried over MgSO₄, then ethereal HCL was added.The solvents were removed under vacuum and the product was crystallizedwith MeOH/ether to produce 500 mg (9%). Mp 182-186° C. MS m/z 344 (M+H).

Example 214

6-{2-Fluoro-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one

Following the procedure of Example 213: Mp 220-222° C. MS m/z 332 (M+H).

Example 215

6-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyridin-2-yl-2H-pyridazin-3-one

In a 50 mL round bottom flask,6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one(250 mg, 0.71 mmol), 2-bromopyridine (105 μL, 1.07 mmol),copper(I)iodide (13.6 mg, 0.07 mmol), and potassium carbonate (296 mg,2.14 mmol) in dimethylformamide (10 mL) was heated to reflux 14 h. Thereaction was cooled and water (20 mL) was added. The sticky solids werefiltered off and then partitioned between methylene chloride and water,separated, and dried over MgSO₄. Purification with silica gelchromatography eluting with methylene chloride/methanol (95:5) produced10 mg (2.4%) oil. MS m/z 391 (M+H).

Example 216 Step 1

4-[4-(3-Chloro-propoxy)-phenyl]-4-oxo-2-pyridin-2-yl-butyric acid ethylester

In a 500 mL round bottom flask ethyl 2-pyridylacetate (2.0 g, 12.1mmol), and 60% sodium hydride (508 mg, 12.7 mmol) in dimethylformamide(50 mL) was stirred 1 h.2-Bromo-1-[4-(3-chloro-propoxy)-phenyl]-ethanone (3.53 g, 12.1 mmol) wasthen added in dimethylformamide (50 mL) via dropping funnel. Thereaction was stirred 14 h. Water (300 mL) was added and the organicswere extracted three times with ethyl acetate, and then dried overMgSO₄. Purification with silica gel chromatography eluting withhexanes/ethyl acetate (3:1) produced 2.8 g (62%). MS m/z 376 (M+H).

Step 2

4-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4-oxo-2-pyridin-2-yl-butyricacid ethyl ester

In a 100 mL round bottom flask,4-[4-(3-chloro-propoxy)-phenyl]-4-oxo-2-pyridin-2-yl-butyric acid ethylester (2.77 g, 7.4 mmol), benzenesulfonate (R)-2-methyl-pyrrolidinium(3.59 g, 14.7 mmol), potassium carbonate (4.07 g, 29.5 mmol), andpotassium iodide (100 mg, 0.6 mmol) in acetonitrile (100 mL) was heatedto reflux 14 h. The reaction was cooled and the solvent concentratedunder vacuum. The slurry was partitioned between methylene chloride andwater, and then washed with water 3 times. The organics werechromatographed through silica gel with methylene chloride/methanol(95:5) eluent. Ethereal HCl was added to make the bis HCl salt andproduce 960 mg (28%) of an amorphous solid. MS m/z 425 (M+H).

Example 216 Step 3

6-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one

In a 50 mL round bottom flask,4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4-oxo-2-pyridin-2-yl-butyricacid ethyl ester (950 mg, 1.84 mmol), and hydrazine monohydrate (204 μL,4.2 mmol), in acetic acid (20 mL) was heated to reflux 14 h. Thereaction was cooled and the solvent concentrated under vacuum. Theslurry was partitioned between methylene chloride and NaHCO₃ sol.,extracted three times, and then dried over MgSO₄. Purification withsilica gel chromatography eluting with methylene chloride/methanol(95:5) produced 250 mg (33%). Ethereal HCl was added to a methanolsolution to produce crystals. Mp 231-233° C. MS m/z 393 (M+H).

Example 217

6-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4-pyridin-2-yl-2H-pyridazin-3-one

In a 10 mL round bottom flask,6-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4-pyridin-2-yl-4,5-dihydro-2H-pyridazin-3-one(120 mg, 0.31 mmol), and cesium carbonate (197 mg, 0.62 mmol), indimethylsulfoxide (3 mL) was heated to 135° C. 3 h. The reaction wascooled and the slurry was partitioned between methylene chloride andwater extracted three times, and then dried over MgSO₄. Purificationwith silica gel chromatography eluting with methylene chloride/methanol(95:5), followed by HCl salt formation produced 120 mg (33%). Mp157-161° C. MS m/z 391 (M+H).

Example 218 Step 1

8-Methoxy-5,6-dihydro-3H-benzo[f]cinnolin-2-one

In a 50 mL round bottom flask, 6-methoxy-3,4-dihydro-1H-naphthalen-2-one(1.0 g, 5.68 mmol), and glyoxylic acid monohydrate (523 mg, 5.68 mmol),in acetic acid (10 mL) was heated to reflux 3 h. The reaction was cooledand diluted with water (20 mL). The mixture was basified to pH 8 withNH₄OH and then hydrazine monohydrate (0.55 mL, 11.4 mmol) was added. Thereaction was heated to reflux 2 h. The reaction was cooled andre-basified with NaHCO₃, then extracted with methylene chloride threetimes. The organics were dried over MgSO₄, and the solvents were removedunder vacuum to produce 1.1 g (85%). mp dec. 270° C. MS m/z=229 (M+H).

Step 2

8-Hydroxy-5,6-dihydro-3H-benzo[f]cinnolin-2-one

In a 100 mL round bottom flask,8-methoxy-5,6-dihydro-3H-benzo[f]cinnolin-2-one (1.05 g, 4.61 mmol) inmethylene chloride (3 mL) was cooled to 0° C. Boron tribromide (23 ml ofa 1M sol. in methylene chloride) was added and the reaction warmed toambient temperature for 4 h. Re-cooled to 0° C. and sat. NH4Cl sol. (23mL) was added. The solvents were removed under vacuum and water wasadded. Solids were filtered off and washed with cold methanol to produce587 mg (59%). Mp>300° C. MS m/z 215 (M+H).

Step 3

8-(3-Chloro-propoxy)-5,6-dihydro-3H-benzo[f]cinnolin-2-one

In a 50 mL round bottom flask,8-hydroxy-5,6-dihydro-3H-benzo[f]cinnolin-2-one (575 mg, 2.69 mmol),1-bromo-3-chloro-propane (0.27 mL, 2.69 mmol), and potassium carbonate(371 mg, 2.69 mmol) in acetonitrile (20 mL) was heated to reflux 14 h.The reaction was cooled and the solvent concentrated under vacuum. Theslurry was partitioned between methylene chloride and water, separated,dried over MgSO₄. Purification with silica gel chromatography elutingwith methylene chloride/methanol (95:5) produced 106 mg (14%) as anamorphous solid. MS m/z 291 (M+H).

Example 218 Step 4

8-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-5,6-dihydro-3H-benzo[f]cinnolin-2-one

In a 25 mL round bottom flask,8-(3-chloro-propoxy)-5,6-dihydro-3H-benzo[f]cinnolin-2-one (100 mg, 0.34mmol), benzenesulfonate (R)-2-methyl-pyrrolidinium (168 mg, 0.68 mmol),potassium carbonate (190 mg, 1.36 mmol), and potassium iodide (1 mg,0.006 mmol) in acetonitrile (10 mL) was heated to reflux 14 h. Thereaction was cooled and the solvent concentrated under vacuum. Theslurry was partitioned between methylene chloride and water, and thenwashed with water 3 times. The organics were chromatographed throughsilica gel with methylene chloride/methanol (95:5) eluent to produce 10mg (9%). Mp 225° C. (dec.). MS m/z 340 (M+H).

Example 219 Step 1

4-(4-Acetyl-3-fluoro-phenoxy)-piperidine-1-carboxylic acid tert-butylester

In a 500 mL round bottom flask, diethyl azodicarboxylate (16.9 g, 97.3mmol) and triphenylphosphine (25.5 g, 97.3 mmol) in tetrahydrofuran (200mL) were cooled to 0° C. 1-(2-Fluoro-4-hydroxy-phenyl)-ethanone (10.0 g,64.9 mmol) and 4-hydroxy-piperidine-1-carboxylic acid tert-butyl ester(15.67 g, 77.9 mmol) in tetrahydrofuran (100 mL) were added. Thereaction was warmed to ambient temperature 14 h. The solvents wereconcentrated under vacuum and methylene chloride (100 mL) and hexanes(500 mL) were added. The solids were filtered off. The mother liquor wasconcentrated under vacuum and chromatographed through silica gel withhexanes/ethyl acetate (7:3) as eluent to produce 17.5 g (80%). Mp 72-73°C.

Step 2

4-[4-(3-Ethoxycarbonyl-propionyl)-3-fluoro-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester

In a 250 mL round bottom flask,4-(4-acetyl-3-fluoro-phenoxy)-piperidine-1-carboxylic acid tert-butylester (4.0 g, 12 mmol) in tetrahydrofuran (00 mL) were cooled to −78° C.Lithium diisopropylamide (1.4 g, 13 mmol) was added and stirred 30 min.then warmed to 0° C. Re-cooled to −78° C. and ethyl bromoacetate (1.4mL, 13 mmol) in tetrahydrofuran (25 mL) was added. The reaction warmedto ambient temperature over 14 h. The reaction was quenched with NH₄Clsol. and the solvents were concentrated under vacuum. The reaction waschromatographed through silica gel with hexanes/ethyl acetate (7:3) aseluent to produce 4.10 g (82%) of oil.

Step 3

4-[3-Fluoro-4-(6-oxo-1,4,5,6-tetrahydro-pyridazin-3-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester

In a 250 mL round bottom flask,4-[4-(3-ethoxycarbonyl-propionyl)-3-fluoro-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester (4.1 g, 9.68 mmol), and hydrazine monohydrate(0.97 mL, 19.4 mmol), in isopropanol (100 mL) was heated to reflux 14 h.The reaction was cooled and the solvent concentrated under vacuum.Purification with silica gel chromatography eluting with methylenechloride/methanol (95:5) produced 945 mg (25%). Mp 146-148° C. MS m/z392 (M+H).

Step 4

6-[2-Fluoro-4-(piperidin-4-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-one

In a 10 mL round bottom flask,4-[3-fluoro-4-(6-oxo-1,4,5,6-tetrahydro-pyridazin-3-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester (410 mg, 1.0 mmol) in trifluoroacetic acid (3 mL)was stirred 2 h. The solvent concentrated under vacuum to produce 420 mg(100%) of the salt as an oil. MS m/z=292 (M+H).

Example 219 Step 5

6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-2-fluoro-phenyl]-4,5-dihydro-2H-pyridazin-3-one

In a 25 mL round bottom flask,6-[2-fluoro-4-(piperidin-4-yloxy)-phenyl]-4,5-dihydro-2H-pyridazin-3-onetrifluoroacetic acid salt (420 mg, 1.0 mmol) was dissolved in methanol(10 mL), N,N-dimethylformamide (4 mL), and acetic acid (0.4 mL).Cyclobutanone (0.23 mL, 3.0 mmol), and then sodium cyanoborohydride(0.32 g, 5.0 mmol) were added. The reaction was heated to 60° C. for 2h. The reaction was cooled and diluted with methylene chloride andNaHCO₃ sol. to pH 9. The organics were extracted three times and thesolvent concentrated under vacuum. Purification with silica gelchromatography eluting with methylene chloride/methanol (95:5) followedby salt formation with ethereal HCl produced 210 mg (54%). Mp>300° C. MSm/z 346 (M+H).

Example 220

8-(1-Cyclobutyl-piperidin-4-yloxy)-4,4a,5,6-tetrahydro-2H-benzo[h]cinnolin-3-one

Following the procedure of Example 219: Mp>300° C. MS m/z=354 (M+H).

Example 221 Step 1

4-[3-Fluoro-4-(6-oxo-1,6-dihydro-pyridazin-3-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester

In a 10 mL round bottom flask,4-[3-fluoro-4-(6-oxo-1,4,5,6-tetrahydro-pyridazin-3-yl)-phenoxy]-piperidine-1-carboxylicacid tert-butyl ester (525 mg, 1.34 mmol), and cesium carbonate (874 mg,2.68 mmol), in dimethylsulfoxide (5 mL) was heated to 135° C. 3 h. Thereaction was cooled and the slurry was partitioned between methylenechloride and water extracted three times, and then dried over MgSO₄.Purification with silica gel chromatography eluting with methylenechloride/methanol (95:5) produced 500 mg (93%). Mp 117-119° C. MS m/z390 (M+H).

Example 221 Step 2

6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-2-fluoro-phenyl]-2H-pyridazin-3-one

Following the final two steps of Example 219: Mp>300° C. MS m/z 344(M+H).

Example 222

6-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-5-methyl-2H-pyridazin-3-one

Following the procedure of Example 221: Mp>300° C. MS m/z 340 (M+H).

Example 223

5-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-oneStep 1

To a round-bottom flask was added4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenol (11.0 g, 50mmol), 1-bromo-3-chloropropane (9.88 mL, 100 mmol), potassium carbonate(20.7 g, 150 mmol), and acetonitrile (100 mL). The reaction mixture washeated to reflux for 24 h. The reaction was cooled to room temperatureand was filtered. The filtrate was concentrated to give crude2-[4-(3-chloro-propoxy)-phenyl]-4,4,5,5-tetramethyl-[1,3,2]dioxaborolane.This material was used for next step without purification.

Step 2

To a round-bottom flask was added crude2-[4-(3-chloro-propoxy)-phenyl]-4,4,5,5-tetramethyl-[1,3,2]dioxaborolane,(R)-2-methyl-pyrrolidine, benzenesulfonic acid salt (24.3 g, 100 mmol),sodium iodide (7.49 g, 50 mmol), potassium carbonate (20.7 g, 150 mmol)and acetonitrile (100 mL). The reaction was heated to reflux for 2.5days and was cooled to room temperature. The reaction was diluted withmethylene chloride (100 mL) and was filtered. The filtrate wasconcentrated. Purification by column chromatography (5% MeOH in CH₂Cl₂)to give 11.3 g (65%, 2 steps) of(R)-2-methyl-1-{3-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenoxy]-propyl}-pyrrolidine.

Step 3

To a round-bottom flask was added2-hydroxymethyl-5-iodo-2H-pyridazin-3-one (2.28 g, 9.05 mmol),(R)-2-methyl-1-{3-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenoxy]-propyl}-pyrrolidine(3.28 g, 9.50 mmol), tetrakis(triphenylphosphine)palladium(0) (2.1 g,1.8 mmol), potassium carbonate (6.25 g, 45.2 mmol), 1,2-dimethoxyethane(80 mL), and water (40 mL). The reaction mixture was flushed withnitrogen for 30 min and was heated to reflux for 48 h. After cooled toroom temperature, the reaction was filtered. The organic layer wasseparated and concentrated. Purification by column chromatography(CH₂Cl₂:MeOH:iPrNH=9:1:0.1) to give 3.31 g (63.5%) of example 223(5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one).

The following examples were prepared using the procedure for example223.

Example Structure Mp (° C) MS m/z 223

160-163 314 (M + H) 5-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 224

183-185 358 (M + H) 2-Methoxymethyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 225

154-156 328 (M + H) 5-{4-[(S)-2-Methyl-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 226

130-133 328 (M + H) 5-{4-[(R)-2-Methyl-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 227

145-148 328 (M + H) 5-[4-((S)-2-Methyl-3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one 228

160-163 328 (M + H) 5-[4-((R)-2-Methyl-3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one 229

175-180 472 (M + H) 5-{3,5-Dibromo-4-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 230

 139-40.5 HCl 372 (M + H)2-Methoxymethyl-5-{2-methyl-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxyl]-phenyl}-2H-pyridazin-3-one 231

186-8  HCl 328 (M + H) 5-{2-methyl-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxyl]-phenyl}-2H-pyridazin-3-one 232

185-97  (dec.) HCl 372 (M + H)2-Methoxymethyl-5-[2-methyl-4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one 233

112-113 328 (M + H) 5-[2-Methyl-4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one 234

119.5-123.5 HCl 384 (M + H)5-[4-(1-Cyclobutyl-piperidin-4-yloxy)-2-methyl-phenyl]-2-methoxymethyl-2H-pyridazin-3-one

Example 235

4-Methoxy-2-methoxymethyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-oneStep 1

To a stirred solution of 4,5-dichloropyridazin-6-one (5.00 g, 30.3 mmol)and N,N-diisopropylethylamine (7.92 mL, 45.5 mmol) in methylenechloride(50 mL) was added slowly, bromomethyl methyl ether (4.79 mL, 60.6 mmol)at room temperature (water-bath). The reaction was stirred for 22 h andwas then concentrated. Purification by column chromatography (1% MeOH inCH₂Cl₂) gave 4.74 g (74.8%) of4,5-dichloro-2-methoxymethyl-2H-pyridazin-3-one.

Step 2

To a stirred solution of 4,5-dichloro-2-methoxymethyl-2H-pyridazin-3one(1.00 g, 4.78 mmol) in 1,4-dioxane (25 mL) at room temperature was addedsodium methoxide (271 mg, 5.02 mmol). After 19 h, the reaction was addedadditional 271 mg of sodium methoxide and was continued to stir for 6 h.The reaction was filtered and the filtrate was concentrated to give 915mg (93% crude) 5-chloro-4-methoxy-2-methoxymethyl-2H-pyridazin-3-one.

Step 3

To a round-bottom flask was added5-chloro-4-methoxy-2-methoxymethyl-2H-pyridazin-3-one (902 mg, 4.41mmol),(R)-2-methyl-1-{3-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenoxy]-propyl}-pyrrolidine(1.67 g, 4.85 mmol), tetrakis(triphenylphosphine)palladium(0) (510 mg,0.44 mmol), potassium carbonate (2.34 g, 22.0 mmol), 1,2-dimethoxyethane(15 mL) and water (15 mL). The reaction mixture was flushed withnitrogen for 30 min and was then heated to reflux for 21 h. After cooledto room temperature, the reaction was extracted with CH₂Cl₂ (100 mL, 50mL). The combined organic layers were washed with water (50 mL), brine,dried (Na₂SO₄), and concentrated. Purification by column chromatography(5% MeOH in CH₂Cl₂) to give 744 mg (43.6%) of example 235(4-methoxy-2-methoxymethyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one)as an oil. MS m/z 388 (M+H).

Example 236

5-Methoxy-2-methoxymethyl-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-oneStep 1

To a stirred solution of 4,5-dichloro-2-methoxymethyl-2H-pyridazin-3one(500 mg, 2.39 mmol) in methanol (12 mL) at room temperature was addedsodium methoxide (258 mg, 4.78 mmol). After stirred for 2 h, thereaction was concentrated. To this residue was added water (20 mL), thenextracted with CH₂Cl₂ (2×50 mL). The combined organic layer was dried(Na₂SO₄) and concentrated to give 480 mg (98%)4-chloro-5-methoxy-2-methoxymethyl-2H-pyridazin-3-one.

Step 2

To a round-bottom flask was added4-chloro-5-methoxy-2-methoxymethyl-2H-pyridazin-3-one (480 mg, 2.34mmol),(R)-2-methyl-1-{3-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenoxy]-propyl}-pyrrolidine(890 mg, 2.60 mmol), tetrakis(triphenylphosphine)palladium(0) (270 mg,0.23 mmol), potassium carbonate (1.24 g, 11.7 mmol), 1,2-dimethoxyethane(15 mL), and water (15 mL). The reaction mixture was flushed withnitrogen for 20 min and was then heated to reflux for 24 h. After cooledto room temperature, the reaction was extracted with CH₂Cl₂ (2×50 mL).The combined organic layers was washed brine, dried (Na₂SO₄), andconcentrated. Purification by column chromatography (8% MeOH in CH₂Cl₂)to give 250 mg (26%) example 236(5-methoxy-2-methoxymethyl-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one).Mp 44-45° C. MS m/z 388 (M+H).

Example 237

5-Methoxy-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one

To a round-bottom flask was added example 231(5-Methoxy-2-methoxymethyl-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one)(1.07 g, 2.76 mmol), methanol (10 mL), and concentrated HCl solution (10mL). The reaction was heated to reflux for 3 days. After cooled to roomtemperature, the reaction was neutralized with 10 N NaOH then 5% NaOHsolution to pH 7. The reaction was concentrated and the residue waswashed with CH₂Cl₂ (100 mL). The CH₂Cl₂ layer was concentrated.Purification by column chromatography (15% MeOH in CH₂Cl₂) to give 350mg (37%) of5-methoxy-4-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one.The product was converted to its hydrochloride salt. Mp 135-140. MS m/z344 (M+H).

Example 238

6-[4-(3-Morpholin-4-yl-propoxy)-phenyl]-2H-pyridazin-3-one Step 1

To a round-bottom flask was added1-[4-(3-chloro-propoxy)-phenyl]-ethanone (10.0 g, 47.0 mmol), morpholine(6.15 mL, 70.5 mmol), sodium iodide (7.05 g, 47.0 mmol), potassiumcarbonate (19.5 g, 141 mmol), and acetonitrile (100 mL). The reactionmixture was heated to reflux for 23 h. The reaction was cooled to roomtemperature and was diluted with methylene chloride (100 mL). Thereaction was filtered and the filtrate was concentrated. Purification bycolumn chromatography (2% MeOH in CH₂Cl₂) to give 10.5 g (85%) of6-[4-(3-morpholin-4-yl-propoxy)-phenyl]-2H-pyridazin-3-one.

Step 2

To a round-bottom flask was added6-[4-(3-morpholin-4-yl-propoxy)-phenyl]-2H-pyridazin-3-one (5.00 g, 19.0mmol), oxo-acetic acid, hydrate (3.51 g, 38.1 mmol), and acetic acid (15mL). The reaction was heated to 111° C. for 2.5 h. After cooled to 0°C., the reaction was added water (25 mL) and NH₄OH solution until pH˜6.To this solution was added hydrazine hydrate (2.76 mL, 57.0 mmol) andwas heated to reflux for 20 h (during which additional 3 eq of hydrazinehydrate was added). The reaction was cooled to room temperature andconcentrated. Purification by column chromatography (20% MeOH in CH₂Cl₂)gave 2.53 g (42%) of example 2386-[4-(3-morpholin-4-yl-propoxy)-phenyl]-2H-pyridazin-3-one.

The following examples were prepared.

Example Structure Mp (° C.) MS m/z 238

156-159 316 (M + H) 6-[4-(3-Morpholin-4-yl-propoxy)-phenyl]-2H-pyridazin-3-one 239

156-158 314 (M + H) 6-{4-[3-((S)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one 240

154-157 300 (M + H) 6-[4-(3-Pyrrolidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one 241

<50 314 (M + H) 6-{4-[3-(Cyclobutyl-methyl-amino)-propoxy]-phenyl}-2H-pyridazin-3-one 242

95-98 328 (M + H) 6-{4-[3-(Cyclopentyl-methyl-amino)-propoxy]-phenyl}-2H-pyridazin-3-one

Example 243

5-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-oneStep 1

To a round-bottom flask was added phenol (5.0 g, 53.1 mmol),1-bromo-3-chloropropane (5.52 mL, 55.8 mmol), potassium carbonate (22.0g, 159 mmol), and acetonitrile (100 mL). The reaction mixture was heatedto reflux for 15 h. To this reaction was then added(R)-2-methyl-pyrrolidine hydrochloride (12.9 g, 106 mmol) and sodiumiodide (7.96 g, 53.1 mmol) at room temperature. The reaction wascontinued to reflux for 24 h. After cooled to room temperature, thereaction was filtered through a pad of Celite eluted with CH₂Cl₂ (100mL). The filtrate was concentrated. Purification by columnchromatography (5% MeOH in CH₂Cl₂) to give 9.02 g (77%) of(R)-2-methyl-1-(3-phenoxy-propyl)-pyrrolidine.

Step 2

To a stirred solution of (R)-2-methyl-1-(3-phenoxy-propyl)-pyrrolidine(1.10 g, 5.02 mmol) and 3-oxa-bicyclo[3.1.0]hexane-2,4-dione (562 mg,5.02 mmol) in 1,2-dichloroethane (25 mL) at 0° C. was added aluminumtrichloride (2.01 g, 15.0 mmol) in small portions. The reaction washeated at 80° C. for 18 h. After cooled to room temperature, thereaction was added crushed ice followed by concentrated HCl solution tobreak down the complex. The water layer was separated from the organiclayer. To this water solution was added hydrazine hydrate (1 mL, 20.6mmol) and was heated to reflux for 4 h. The reaction was cooled to roomtemperature and concentrated. Purification by column chromatography (10%MeOH in CH₂Cl₂) gave 1.38 g (76%) of example 243(5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one).

The following examples were synthesized. The racemic isomers of example243 were separated into two enantiomers example 246 and example 247 andexample 244 were separated into two enantiomers example 248 and example249 by chiral chromatography using chiralPak and 0.1% diethylamine inmethanol.

Example Structure Mp (° C.) MS m/z 243

136-139 HCl 328 (M + H) 5-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one 244

79-81 340 (M + H) 5-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one 245

112-115 342 (M + H) 5-{4-[(S)-2-Methyl-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxyl-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one 246 singleisomer

210-211 HCl 328 (M +H) 5-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl]-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one 247 single isomer

197-198 HCl 328 (M + H) 5-{4-[3-((R)-2-Methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one 248 single isomer

186-187 340 (M + H) 5-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one 249 single isomer

185-186 340 (M + H) 5-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one

Examples 250-254 were prepared as HCl salts following the method ofexample 243 and example 244.

Example Structure Mp (° C.) MS m/z 250

246-248 368 (M + H) 5-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-3-ethyl-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one 251

110-112 382 (M + H) 5-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-3-isopropyl-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one 252

243-245 354 (M + H) 5-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-3-methyl-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one 253

147-149 434 (M + H) 5-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-3-(4-fluoro-phenyl)-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one 254

110-121 422 (M + H)5-[4-(1-Cyclobutyl-piperidin-4-yloxy)-phenyl]-3-(2,2,2-trifluoro-ethyl)-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one 260

264-266 HCl 368 (M + H) 5-[4-(1-Cyclopentyl-piperidin-4-yloxy)-phenyl]-3-methyl-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one 261

288-290 HCl 354 (M + H) 5-[4-(1-Cyclopentyl-piperidin-4-yloxy)-phenyl]-3,4-diaza-bicyclo[4.1.0]hept-4-en-2-one

Example 255

6-[4-(2-Hydroxy-3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-oneStep 1

4-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)phenol (1.00 g, 4.50mmol) and anhydrous potassium carbonate (2.20 g, 15.90 mmol) were takenup in racemic epibromohydrin (45 mL).

Reaction mixture was refluxed for 12 h. Potassium carbonate was filteredoff and epibromohydrin was evaporated under vacuum. Purification of theproduct using ISCO silica gel chromatography (hexanes/ethyl acetate 9:1)gave a white solid 1.25 g.

Step 2

The product from step 1 (0.50 g, 1.80 mmol) and piperidine (0.23 g, 2.70mmol) were dissolved in EtOH and refluxed for 5 h. The solvent wasevaporated and the product was purified by ISCO silica gelchromatography eluting with EtOAc/MeOH 9:1 to give product as a whitesolid 0.49 g (75%).

Step 3

THF anhydrous 15 mL was added to Pd(OAc)₂ (0.08 g, 0.35 mmol) andtriphenylphosphine (0.38 g, 1.40 mmol) under N₂. The reaction wasstirred for 5 min and 3,6-dichloropyridazine (1.00 g, 6.70 mmol) wasadded and reaction mixture was stirred for another 5 min. The productfrom step 2(1-piperidin-1-yl-3-[4-(4,4,5,5-tetramethyl-[1,3,2]-dioxaborolan-2-yl)phenoxy]-propan-2-ol)(0.49 g, 1.35 mmol) in 9 mL of anhydrous THF and 5 mL of EtOH was addeddropwise, followed by 15 mL of saturated NaHCO₃.

The reaction mixture was heated at 82° C. overnight. The solvent wasremoved and the residue was taken up in methylene chloride and washedwith H₂O and saturated NaCl, dried over Na₂SO₄ and was evaporated. Theproduct was purified by ISCO silica gel chromatography eluting withEtOAc/MeOH 9:1 to obtain 0.22 g (46%).

Step 4

The product from step 3 (0.18 g, 0.50 mmol) in 7 mL of glacial aceticacid and NaOAc (0.02 g, 0.25 mmol) was heated to 115° C. for 2 h. Thesolvent was coevaporated with toluene and the residue was taken up inMeOH and catalytic amount of K₂CO₃ was added. After 1 h at reflux, thesolvent was evaporated and the product was purified by ISCO silica gelchromatography eluting with EtOAc/MeOH 9:1 to give a white solid 0.09 g(82%); Mp 185° C.; MS m/z 330 (M+H).

Example 256

6-{4-[2-Hydroxy-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one

Example 256 was synthesized using the method for example 255 to give awhite solid 0.07 g (54%); Mp 153° C.; MS m/z 330 (M+H).

Example 257

6-{4-[(S)-2-Hydroxy-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one

Example 257 was synthesized using the method for example 256 exceptusing (S)-(+)-epichlorohydrin to give example 257 as a white solid 0.16g (46%); Mp 156° C.; MS m/z 330 (M+H).

Example 258

6-{4-[(R)-2-Hydroxy-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one

Example 258 was synthesized using the method for example 256 exceptusing (R)-(−)-epichlorohydrin to give example 258 as a white solid 0.16g, (44%); Mp 147° C.; MS m/z 330 (M+H).

Example 259

6-[4-((R)-2-Hydroxy-3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one

Example 259 was synthesized using the method for example 255 using(R)-(−)-epichlorohydrin to give example 259 as a white solid 0.14 g,(48%); Mp 167° C.; MS m/z 330 (M+H).

Utility

The compounds of the present invention are useful, inter alia, astherapeutic agents. Particularly, the compounds are useful forinteracting with the H₃ receptor. In one embodiment, the presentinvention provides a method for treating or preventing diseases anddisorders, such as those disclosed herein, which comprises administeringto a subject in need of such treatment or prevention a therapeuticallyeffective amount of a compound of the present invention.

In an additional embodiment, the present invention provides a method forinhibiting H₃ activity comprising providing a compound of the presentinvention in an amount sufficient to result in effective inhibition.Particularly, the compounds of the present invention can be administeredto treat such diseases and disorders such as narcolepsy or sleep/wakedisorders, feeding behavior, eating disorders, obesity, cognition,arousal, memory, mood disorders, mood attention alteration, attentiondeficit hyperactivity disorder (ADHD), Alzheimer's disease/dementia,schizophrenia, pain, stress, migraine, motion sickness, depression,psychiatric disorders, epilepsy, gastrointestinal disorders, respiratorydisorders (such as asthma), inflammation, and myocardial infarction. Incertain embodiments, the compounds can be administered to treatnarcolepsy or sleep/wake disorders, obesity, cognition, attentiondeficit hyperactivity disorder (ADHD), and dementia. In otherembodiments, the compounds can be administered to treat narcolepsy orsleep/wake disorders, or they can used to treat obesity, or they canused to treat cognition, or they can used to treat attention deficithyperactivity disorder (ADHD), or they can used to treat dementia.

The inhibition of enzymatic activity by the compounds of the presentinvention can be determined using, for example, the following assays asset forth below. They are not intended, nor are they to be construed, aslimiting the scope of the disclosure.

Rat H₃ Assays:

Cell Line Development and Membrane Preparation.

The rat H₃ receptor cDNA was PCR amplified from reverse-transcribed RNApooled from rat thalamus, hypothalamus, striatum and prefrontal cortexwith a sequence corresponding to by #338-1672 of Genbank file#NM_(—)053506, encoding the entire 445-amino-acid rat histamine H₃receptor. This was engineered into the pIRES-neo3 mammalian expressionvector, which was stably transfected into the CHO-A3 cell line(Euroscreen, Belgium), followed by clonal selection by limitingdilution. Cells were harvested and cell pellets were frozen (−80° C.).Cell pellets were resuspended in 5 mM Tris-HCl, pH 7.5 with 5 nM EDTAand a cocktail of protease inhibitors (Complete Protease InhibitionTablets, Roche Diagnostics). Cells were disrupted using a polytron cellhomogenizer and the suspension was centrifuged at 1000×g for 10 minutesat 4° C. The pellet was discarded and the supernatant centrifuged at40,000×g for 30 min at 4° C. This membrane pellet was washed in membranebuffer containing 50 mM Tris-HCl, pH 7.5 with 0.6 mM EDTA, 5 mM MgCl₂and protease inhibitors, recentrifuged as above and the final pelletresuspended in membrane buffer plus 250 mM sucrose and frozen at −80° C.

Radioligand Binding.

Membranes were resuspended in 50 mM Tris HCl (pH 7.4), 5 mM MgCl₂, 0.1%BSA. The membrane suspensions (10 μg protein per well) were incubated ina 96 well microtiter plate with [³H]-N-alpha-methylhistamine(approximately 1 nM final concentration), test compounds at variousconcentrations (0.01 nM-30 μM) and scintillation proximity beads (PerkinElmer, FlashBlueGPCR Scintillating Beads) in a final volume of 80 μl for4 hours at room temperature, protected from light. Non-specific bindingwas determined in the presence of 10 μM clobenpropit. Radioligand boundto receptor, and therefore in proximity to the scintillation beads, wasmeasured using a MicroBeta scintillation counter.

GTPγS Binding.

Membranes were resuspended in 20 mM HEPES pH 7.4 containing: 1 mM EDTA,0.17 mg/ml dithiothreitol, 100 mM NaCl, 30 μg/ml saponin and 5 mM MgCl₂.For measurement of inverse agonist activity, increasing concentrationsof test compounds were incubated in a 96 well microtiter plate with 10μg/well membrane protein, 5 μM GDP, scintillation proximity beads(Perkin Elmer, FlashBlueGPCR Scintillating Beads) and [³⁵S]-GTPγS (0.1nM final concentration). Following incubation for 45 minutes in the darkat room temperature, the microtiter plate was centrifuged at 1000×g for5 minutes and radioactivity bound to the membranes was counted using aMicroBeta scintillation counter. Non-specific binding was measured inthe presence of 10 μM GTP. A decrease in bound [³⁵S]-GTPγS is indicativeof H₃ receptor inverse agonist activity in this assay. Antagonistactivity of test compounds was determined in a similar experiment underthe following conditions. Membranes were resuspended in 20 mM HEPES pH7.4 containing: 1 mM EDTA, 0.17 mg/ml dithiothreitol, 200 mM NaCl, 30μg/ml saponin and 20 mM MgCl₂. The membranes were incubated at 10μg/well membrane protein in a microtiter plate with increasingconcentrations of test compounds, 20 μM GDP, scintillation proximitybeads and [³⁵S]-GTPγS (0.1 nM final concentration) plus 30 nMR-alpha-methylhistamine. The microtiter plates were incubated andprocessed as described above. A decrease in R-alpha-methylhistaminestimulated [³⁵S]-GTPγS binding is indicative of H₃ receptor antagonistactivity in this assay.

Human H₃ Assays:

Methods:

CHO cells stably expressing the human H₃ receptor (GenBank:NM_(—)007232) were harvested and cell pellets were frozen (−80° C.).Cell pellets were resuspended in 5 mM Tris-HCl, pH 7.5 with 5 nM EDTAand a cocktail of protease inhibitors (Complete Protease InhibitionTablets, Roche Diagnostics). Cells were disrupted using a polytron cellhomogenizer and the suspension was centrifuged at 1000×g for 10 minutesat 4° C. The pellet was discarded and the supernatant centrifuged at40,000×g for 30 min at 4° C. This membrane pellet was washed in membranebuffer containing 50 mM Tris-HCl, pH 7.5 with 0.6 mM EDTA, 5 mM MgCl₂and protease inhibitors, recentrifuged as above and the final pelletresuspended in membrane buffer plus 250 mM sucrose and frozen at −80° C.

Radioligand Binding.

Membranes were resuspended in 50 mM Tris HCl (pH 7.4), 5 mM MgCl₂, 0.1%BSA. The membrane suspensions (10 μg protein per well) were incubated ina 96 well microtiter plate with [³H]-N-alpha-methylhistamine(approximately 1 nM final concentration), test compounds at variousconcentrations (0.01 nM-30 μM) and scintillation proximity beads (PerkinElmer, FlashBlueGPCR Scintillating Beads) in a final volume of 80 μl for4 hours at room temperature, protected from light. Non-specific bindingwas determined in the presence of 10 μM clobenpropit. Radioligand boundto receptor, and therefore in proximity to the scintillation beads, wasmeasured using a MicroBeta scintillation counter.

GTPγS Binding.

Membranes were resuspended in 20 mM HEPES pH 7.4 containing: 1 mM EDTA,0.17 mg/ml dithiothreitol, 100 mM NaCl, 30 μg/ml saponin and 5 mM MgCl₂.For measurement of inverse agonist activity, increasing concentrationsof test compounds were incubated in a 96 well microtiter plate with 10μg/well membrane protein, 5 μM GDP, scintillation proximity beads(Perkin Elmer, FlashBlueGPCR Scintillating Beads) and [³⁵S]-GTPγS (0.1nM final concentration). Following incubation for 45 minutes in the darkat room temperature, the microtiter plate was centrifuged at 1000×g for5 minutes and radioactivity bound to the membranes was counted using aMicroBeta scintillation counter. Non-specific binding was measured inthe presence of 10 μM GTP. A decrease in bound [³⁵S]-GTPγS is indicativeof H₃ receptor inverse agonist activity in this assay. Antagonistactivity of test compounds was determined in a similar experiment underthe following conditions. Membranes were resuspended in 20 mM HEPES pH7.4 containing: 1 mM EDTA, 0.17 mg/ml dithiothreitol, 200 mM NaCl, 30μg/ml saponin and 20 mM MgCl₂. The membranes were incubated at 10μg/well membrane protein in a microtiter plate with increasingconcentrations of test compounds, 20 μM GDP, scintillation proximitybeads and [³⁵S]-GTPγS (0.1 nM final concentration) plus 30 nMR-alpha-methylhistamine. The microtiter plates were incubated andprocessed as described above. A decrease in R-alpha-methylhistaminestimulated [³⁵S]-GTPγS binding is indicative of H₃ receptor antagonistactivity in this assay.

Other assays that may be used in connection with the present inventionare set forth below. Examples of the present invention can be tested inthe following in vivo models:

Evaluation of Wake Promoting Activity in Rats

The methodology utilized for evaluating wake promoting activity of testcompounds is based on that described by Edgar and Seidel, Journal ofPharmacology and Experimental Therapeutics, 283:757-769, 1997, andincorporated herein in its entirety by reference. Compounds of theinvention either have demonstrated or are expected to demonstrateutility for wake promoting activity.

Dipsogenia Model:

Inhibition of histamine agonist-induced water drinking in the rat.Histamine, and the H₃-selective agonist (R)-α-methylhistamine (RAMH)induce water drinking behavior in the rat when administered eitherperipherally or centrally (Kraly, F. S., June, K. R. 1982 Physiol.Behav. 28: 841; Leibowitz, S. F. 1973 Brain Res. 63:440; Ligneau X.,Lin, J-S., Vanni-Mercier G., Jouvet M., Muir J. L., Ganellin C. R.,Stark H., Elz S., Schunack W., Schwartz, J-C. 1998 J Pharmcol. Exp.Ther. 287:658-66; Clapham, J. and Kilpatrick G. J. 1993 Eur. J.Pharmacol. 232:99-103) an effect which is blocked by H₃ receptorantagonists thioperamide and ciproxifan. Compounds of the inventioneither have demonstrated or are expected to block RAMH induce waterdrinking behavior.

Novel Object Discrimination:

Novel object discrimination (NOD; also referred to as novel objectrecognition) is an assay for short-term visual recognition memory thatwas first described by Ennaceur and Delacour (Ennaceur, A. and Delacour,J. (1988) Behav Brain Res 31: 47-59).

Social Recognition:

Social recognition (SR) is an assay for short-term social (olfactory)memory that was first described by Thor and Holloway (1982). Thor, D.and Holloway, W. (1982) J Comp Physiolog Psychcol 96: 1000-1006.

Table A lists the Human and H₃ binding data for Examples 1-78 and 81 ofthe present invention.

TABLE A H3 Pyridazinone Binding data Human H₃ Rat H₃ Example Ki nM Ki nM1 A A 2 A B 3 A A 4 A A 5 A A 6 A A 7 A A 8 A A 9 A A 10 A B 81 A A 11 AA 12 A A 13 A A 14 A A 15 B C 16 A A 17 A A 18 A A 19 A A 20 A A 21 A C22 A A 23 A B 24 A A 25 B D 26 A D 27 D D 28 A B 29 A A 30 A C 31 A B 32A A 33 A B 34 A A 35 B B 36 B D 37 A B 38 A A 39 A A 40 A A 41 A A 42 BB 43 A A 44 A B 45 A A 46 A B 47 A A 48 A A 49 A A 50 A A 51 A D 52 A A53 A A 54 A A 55 A A 56 A A 57 A A 58 A A 59 A A 60 A A 61 A A 62 D D 63D D 64 A B 65 D D 66 D D 67 B D 68 A B 69 B D 70 B B 71 B C 72 A A 73 CD 74 A A 75 A A 76 A A 77 A B 78 A A 79 80 Binding constants (K_(i)) forExamples 1 to 78 and 81 in the Human H₃ and Rat H₃ methods describedherein are expressed by letter descriptor to indicate the followingranges: A is 0.1-100 nM; B is 101-500 nM; C is 501-1000 nM; and Dis >1000 nM.

Table B lists the Human and Rat H₃ binding data for Examples 82-262 ofthe present invention. The Example numbers in the Table correspond tothe Actual Example numbers in the Examples Section.

TABLE B H3 Pyridazinone Binding data human H3 rat H3 Ki Example Ki (nM)(nM) 81 A A 82 A A 83 A A 84 A A 85 A A 86 A A 87 A A 88 A A 89 A A 90 A5 91 A A 92 A A 93 A A 94 A A 95 A A 96 A A 97 A A 98 A A 99 A A 100 A A101 A A 102 D D 103 A A 104 A A 105 D D 106 A A 107 A A 108 A A 109 A A110 A A 111 A A 112 A 113 D D 114 A A 115 A A 116 A A 117 A A 118 A A119 A A 120 A B 121 A A 122 A A 123 A A 124 A A 125 B C 126 B C 127 C C128 A A 129 A B 130 B B 131 A A 132 A A 133 A A 134 A A 135 B B 136 A B137 A A 138 A A 139 A A 140 B C 141 A A 142 A B 143 A C 143 A A 144 A A145 A A 146 A A 147 A B 148 A A 149 A A 150 A A 151 A A 152 A A 153 A A154 A A 155 A A 156 A A 157 A A 158 A A 159 D D 160 B B 161 D D 162 C D163 A A 164 A A 165 D D 166 A A 167 A A 168 A A 169 A A 170 A A 171 A A172 A A 173 A A 174 A A 175 A A 176 A A 177 A A 178 A A 179 A A 180 A A181 A B 182 A A 183 A A 184 A A 185 A A 186 A A 187 A A 188 A A 189 A A190 A A 191 A A 192 4 A 193 A A 194 A A 195 A A 196 A A 197 A A 198 A A199 A A 200 A A 201 A B 202 A A 203 A A 204 A A 205 B B 206 D D 207 A A208 A A 209 A A 210 A A 211 A A 212 A A 213 B B 214 A A 215 A A 216 A A217 A A 218 A A 219 A A 220 A A 221 A A 222 A A 223 A A 224 A A 225 A A226 A A 227 A A 228 A B 229 A C 230 A A 231 A A 232 A A 233 A B 234 A A235 A A 236 A A 237 A A 238 D D 239 A A 240 A A 241 B B 242 A B 243 A A244 A A 245 A A 246 A A 247 A A 248 A A 249 A A 250 A A 251 A A 252 A A253 A A 254 A A 255 B B 256 A B 257 A A 258 A A 259 B B 260 A A 261 A A262 A B Binding constants (K_(i)) for Examples 1 to 78 and 81 in theHuman H₃ and Rat H₃ methods described herein are expressed by letterdescriptor to indicate the following ranges: A is 0.1-100 nM; B is101-500 nM; C is 501-1000 nM; and D is >1000 nM.

Compounds of the invention either have demonstrated or are expected todemonstrate inhibition of H₃ and thereby for utility for treatment ofthe indications described herein.

Publications cited throughout this disclosure are incorporated in theirentirety herein by reference.

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What is claimed:
 1. A compound according to formula (Ia):

or a stereoisomeric form, mixture of stereoisomeric forms, or apharmaceutically acceptable salt thereof, wherein: Y is S(O)_(q) or O orNR¹⁵; R¹ is selected from a pyrrolidinyl or piperidinyl ring, optionallysubstituted with 1 to 3 R²⁰ groups; R² is

each R³ is independently H, F, Cl, Br, I, OR²¹, NR²³R²⁴, NO₂, CN, CF₃,C₁-C₆alkyl, C(═O)R²¹, CO₂R²¹, or C(═O)NR²³R²⁴; or when R³ is ortho toR², then R³ and R¹⁴ taken together may form —(CH₂)_(s)—, —CH₂Z—, —ZCH₂—,—ZCH₂CH₂— or CH₂CH₂Z—; wherein Z is O or S(O)_(y); or when R³ is orthoto R², then R³ and R¹³ taken together may form —(CH₂)_(s)—, —CH₂Z—,—ZCH₂—, —ZCH₂CH₂— or CH₂CH₂Z—; each R⁴ is independently H, C₁-C₆alkyl,or C₁-C₆ alkoxyl, wherein the alkyl or alkoxyl group is optionallysubstituted with 1 to 3 R²⁰ groups; R¹² is H, C₁-C₆alkyl, cycloalkyl,aryl, arylalkyl, heteroaryl, heterocycloalkyl, C(═O)R²⁷, or CO₂R²⁷,wherein the alkyl, cycloalkyl, aryl, arylalkyl, heteroaryl, orheterocycloalkyl group is optionally substituted with 1 to 3 R²⁰ groups;R¹³ and R¹⁴ are each independently H, C₁-C₆alkyl, aryl, arylalkylC₁-C₆alkoxyl, S(═O)_(y)—C₁-C₆alkyl, cycloalkyl, heterocycloalkyl, orheteroaryl; R¹⁵ is H, C₁-C₆ alkyl, C(═O)R²⁵, or CO₂R²⁵; R²⁰ at eachoccurrence is independently, H, F, Cl, Br, I, OR²¹, NR²³R²⁴, NHOH, NO₂,CN, CF₃, C₁-C₆ alkyl optionally substituted with OR²⁶, C₂-C₆ alkenyl,C₂-C₆ alkynyl, C₃-C₇cycloalkylC₀-C₄alkyl, 3- to 7-memberedheterocycloalkylC₀-C₄alkyl, phenyl, 5- or 6-memberedheteroarylC₀-C₄alkyl, arylalkyl, (═O), C(═O)R²¹, CO₂R²¹, OC(═O)R²¹,C(═O)NR²³R²⁴, NR²⁷C(═O)R²¹, NR²⁷C(═O)OR²¹, OC(═O)NR²³R²⁴, NR²⁷C(═S)R²¹,or S(O)_(q)R²¹; each R²¹ is independently H, C₁-C₆alkyl, aryl, orarylalkyl; each R²³ and R²⁴ is independently selected from H,C₁-C₆alkyl, and aryl, or R²³ and R²⁴, together with the nitrogen atom towhich they are attached, form a 3 to 7 membered heterocyclic ringoptionally substituted with ═O; R²⁵ is C₁-C₆alkyl, aryl, or alkylaryl;R²⁶ is H, C₁-C₆alkyl, aryl, or alkylaryl; R²⁷ is H or C₁-C₆alkyl; m is1, 2, 3, 4, or 5 when R¹ is attached via a nitrogen atom, and m is 0, 1,2, 3, 4, or 5 when R¹ is attached via a carbon atom; n is 1 or 2; q is0, 1, or 2; s is 1, 2, or 3; and y is 0, 1, or
 2. 2. A compoundaccording to claim 1, wherein Y is O.
 3. A compound according to claim1, wherein the optionally substituted piperidinyl or pyrrolidinyl ringof R¹ is attached to Y through a ring nitrogen atom.
 4. A compoundaccording to claim 1, wherein R¹ is a piperidinyl ring attached to Ythrough a ring carbon atom and is optionally substituted with 1 to 3 R²⁰groups.
 5. A compound according to claim 4, wherein the piperidinyl ringis N-substituted with cycloalkyl.
 6. A compound according to claim 1,wherein R¹² is H, C₁-C₆alkyl, cycloalkyl, aryl, arylalkyl, orheteroaryl.
 7. A compound according to claim 6, wherein R¹² is H orheteroaryl.
 8. A compound according to claim 7, wherein when R¹² isheteroaryl, and said heteroaryl is pyridinyl or thienyl.
 9. A compoundaccording to claim 1, wherein R¹² is H or heteroaryl, and R¹³ and R¹⁴are each H or alkyl.
 10. A compound according to claim 1, wherein R¹² isheteroaryl, and R¹³ and R¹⁴ are each H or alkyl.
 11. A compoundaccording to claim 1, wherein R¹⁴ is heteroaryl.
 12. A compoundaccording to claim 2, wherein at least one R³ is F, Cl, Br, orC₁-C₆alkyl.
 13. A compound according to claim 1, wherein R⁴ is H, orC₁-C₆ alkyl.
 14. A compound according to claim 13, wherein R⁴ is H. 15.A compound according to claim 4, wherein m is 0 or
 1. 16. A compoundaccording to claim 1, wherein m is
 3. 17. A compound according to claim3, wherein m is
 3. 18. A compound according to claim 1, wherein R¹ is:


19. A compound according to claim 18, wherein R¹ is:


20. A compound according to claim 18, wherein R²⁰ is F, Cl, CF₃,NR²³R²⁴, or C₁-C₆alkyl optionally substituted with OR²⁶,cycloalkylC₀-C₄alkyl, or heterocycloalkylC₀-C₄alkyl.
 21. A compoundaccording to claim 20, wherein R²⁰ is C₁-C₆alkyl optionally substitutedwith OR²⁶.
 22. A compound according to claim 1, wherein Y—(CHR⁴)_(m)—R¹is:


23. A compound according to claim 1, wherein R² is:

and R¹² is C₁-C₆ alkyl, aryl, arylalkyl, or heteroaryl optionallysubstituted with 1 to 3 R²⁰ groups.
 24. A compound according to claim 1,selected from the group consisting of:2,6-dimethyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;2,6-dimethyl-5-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;6-methyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;6-methyl-5-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;2-methyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;2-methyl-5-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyridin-2-yl-2H-pyridazin-3-one;5-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2-pyridin-2-yl-2H-pyridazin-3-one;2-methyl-5-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;2-(6-methyl-pyridin-2-yl)-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;2-(3-methyl-pyridin-2-yl)-5-{4-[3-((R)-2-methylpyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;6-methyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyridin-2-yl-2H-pyridazin-3-one;6-methyl-2-(3-methyl-pyridin-2-yl)-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;6-methyl-5-[4-(piperidin-4-yloxy)-phenyl]-2H-pyridazin-3-one;5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-6-methyl-2H-pyridazin-3-one;5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-6-methyl-2-pyridin-2-yl-2H-pyridazin-3-one;5-[4-(piperidin-4-yloxy)-phenyl]-2H-pyridazin-3-one;5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-2H-pyridazin-3-one;5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-6-methyl-2-thiophen-3-yl-2H-pyridazin-3-one;6-methyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-thiophen-3-yl-2H-pyridazin-3-one;5-{-4-[3-((S)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyridin-2-yl-2H-pyridazin-3-one;2-isopropyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;8-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-5,6-dihydro-3H-benzo[f]cinnolin-2-one;5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;2-methoxymethyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;5-{4-[(S)-2-methyl-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;5-{4-[(R)-2-methyl-3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;5-[4-((S)-2-methyl-3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;5-[4-((R)-2-methyl-3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;5-{3,5-dibromo-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;2-methoxymethyl-5-{2-methyl-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;5-{2-methyl-4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;2-methoxymethyl-5-[2-methyl-4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;5-[2-methyl-4-(3-piperidin-1-yl-propoxy)-phenyl]-2H-pyridazin-3-one;5-[4-(1-cyclobutyl-piperidin-4-yloxy)-2-methyl-phenyl]-2-methoxymethyl-2H-pyridazin-3-one;and4-methoxy-2-methoxymethyl-5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;or a stereoisomeric form, mixture of stereoisomeric forms, or apharmaceutically acceptable salt thereof.
 25. A compound according toclaim 1, selected from the group consisting of:5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2-pyridin-2-yl-2H-pyridazin-3-one;5-[4-(3-piperidin-1-yl-propoxy)-phenyl]-2-pyridin-2-yl-2H-pyridazin-3-one;5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-6-methyl-2H-pyridazin-3-one;and5-{4-[3-((R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-2H-pyridazin-3-one;or a stereoisomeric form, mixture of stereoisomeric forms, or apharmaceutically acceptable salt thereof.
 26. A pharmaceuticalcomposition comprising a compound of claim 1 or a stereoisomeric form,mixture of stereoisomeric forms, or a pharmaceutically acceptable saltthereof and one or more pharmaceutically acceptable excipients.
 27. Acompound selected from the group consisting of:5-[4-(3-azepan-1-yl-propoxy)-phenyl]-6-methyl-2H-pyridazin-3-one;5-[4-(3-azepan-1-yl-propoxy)-phenyl]-2-methyl-2H-pyridazin-3-one;5-[4-(3-azepan-1-yl-propoxy)-phenyl]-2-pyridin-2-yl-2H-pyridazin-3-one;and5-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-6-methyl-4,5-dihydro-2H-pyridazin-3-one;or a stereoisomeric form, mixture of stereoisomeric forms, or apharmaceutically acceptable salt thereof.